University  Library 
University  of  California  •  Berkeley 


DEPARTMENT  OF  THE  INTERIOR 
FRANKLIN  K.  LANE,  Secretary 


UNITED  STATES   GEOLOGICAL  SURVEY 

GEORGE  OTIS  SMITH,  Director 


BULLETIN  620— K          . 


RECENT  ALUNITE  DWE^MENTS  NEAR 
MARYSVALE  AND  JRAVER/  ufelH 

r\/\    /      //  i 


BY 

G.  F.  LOUGHLIN 


Contributions  to  economic  geology,  1915,  Part  I 
(Pages  237-270) 

Published  December  3, 1915 


WASHINGTON 

GOVERNMENT   PRINTING   OFFICE 
1915 


DEPARTMENT  OF  THE  INTERIOR 

FRANKLIN  K.  LANE,  Secretary 


UNITED  STATES  GEOLOGICAL  SURVEY 

GEORGE  OTIS  SMITH,  Director 


Bulletin  620— K 


RECENT  ALUNITE  DEVELOPMENTS  NEAR 
MARYSVALE  AND  BEAVER,  UTAH 


BY 


.  F.ILOUGHLIN 


G.F.JLC 


Contributions  to  economic  geology,  1915,  Part  II 
( Pages  237-270 ) 

Published  December  3, 1915 


WASHINGTON 

GOVERNMENT    PRINTING    OFFICE 
1915 


CONTENTS. 


Page. 

Introduction 237 

Geology  of  the  Tusliar  Mountains 239 

Alunite  deposits  southwest  of  Marysvale 240 

Location  and  extent 240 

Character 241 

General  features 241 

Detailed  descriptions 242 

Alunite 242 

Quartz 244 

Wall  rock .' 245 

Chemical  composition 246 

Prospects 248 

Principal  groups 248 

Western  zone 248 

Middle  zone 250 

Eastern  zone '. 250 

Other  prospects 252 

Iron  Blossom  group 252 

Gillan's  claims 252 

Santa  Kruze  claims 253 

Mohawk  group '. 253 

Lost  Horse  group 253 

Origin  of  the  deposits 253 

Persistence  in  depth 255 

Suggestions  regarding  development 256 

Estimate  of  tonnage 257 

Deposits  on  west  slope  of  mountains 258 

Localities 258 

Sheep  Rock  deposit 258 

Location  and  extent 258 

Character  of  deposit 259 

Detailed  description 260 

Relation  to  metalliferous  deposits 261 

Origin 262 

Chemical  composition 263 

Commercial  value 263 

Utilization  of  alunite 264 

Products 264 

Potassium  sulphate 264 

Potash  alum 266 

Alumina  and  aluminum  products 269 

Sulphuric  acid  and  sulphur 270 

Fertilizer 270 

III 


ILLUSTRATIONS. 


Page. 

FIGURE  13.  Index  map  showing*  location  of  alunite  deposits  near  Marys- 
vale  and  Beaver,  Utah 238 

14.  Map  showing  location  of  prospects  in  the  principal  group  of 

alunite  deposits  near  Marysvale,  Utah 240 

15.  Geologic   sketch   map   showing  relation  of  the   Sheep   Rock 

quartz-alunite  deposit  near  Beaver,  Utah,  to  country  rock 

and  metalliferous  veins 259 

IV 


RECENT  ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE 
AND  BEAVER,  UTAH. 


By  G.  F.  LOUGHLIN. 


INTRODUCTION. 

In  1910  certain  deposits  of  "  pink  spar  "  about  7  miles  southwest 
of  Marysvale,  Utah,  were  recognized  as  alunite,  the  double  sulphate 
of  aluminum  and  potassium.  Since  January,  1911,  many  alunite  lo- 
cations have  been  made  in  this  region.  Prospecting  and  development 
have  been  essentially  continuous  in  the  hope  of  developing  a  commer- 
cial source  of  potash  salts,  and  this  hope  now  appears  to  have  been 
realized.  The  greatest  amount  of  development  work  has  been  done 
on  the  Gillan-Custer  group  of  claims,  operated  by  the  Mineral 
Products  Corporation,  of  Marysvale. 

A  demonstration  of  the  feasibility  of  extracting  potassium  sul- 
phate from  alunite,  by  W.  T.  Schaller,  was  published  by  the  United 
States  Geological  Survey,  on  December  18,  1911. 1  This  process  has 
been  worked  out  on  a  commercial  scale  by  the  Mineral  Products  Cor- 
poration, which  recently  erected  the  first  mill  for  the  treatment  of 
alunite  in  the  country  and  made  its  first  production  of  potassium  sul- 
phate on  October  7,  1915.  On  October  20  a  carload  of  28  tons  of 
potassium  sulphate,  reported  to  be  93  per  cent  pure,  was  shipped  in 
cotton  bags  to  the  Armour  Fertilizer  Works,  at  Jacksonville,  Fla.2 
It  is  reported  that  at  least  one  other  company  has  plans  for  the 
erection  of  a  mill. 

The  first  discoveries  on  the  Gillan-Custer  group  of  claims  were 
visited  by  C.  W.  Hayes,  then  chief  geologist  of  the  United  States 
Geological  Survey,  in  March,  1911,  and  were  later  examined  by  B.  S. 
Butler  and  H.  S.  Gale,  the  results  of  whose  work,  including  a  general 
geologic  reconnaissance  of  the  Marysvale  region,  were  published  in 
1912.3  Public  interest  in  the  more  recent  developments  prompted 
a  second  examination  of  the  region  in  1914,  and  this  field  work  forms 

1TJ.  S.  Geol.  Survey  Press  Bull.  30,  1911. 

2  Telegram  from  Charles  H.  MacDowell,  president  Armour  Fertilizer  Works  :  Manufac- 
turers Record,  Oct.  21,  1915,  p.  52.     A  private  letter  from  Gascoyne  &  Co.,  Baltimore, 
Md.,  dated  Nov.  10,  1915,  reports  that  analysis  of  potash  of  this  shipment  showed  95.39 
per  cent  of  potassium  sulphate. 

3  Butler,  B.  S.,  and  Gale,  H.  S.,  Alunite,  a  newly  discovered  deposit  near  Marysvale, 
Utah:  U.  S.  Geol.  Survey  Bull.  511,  January,  1912.     See  also  U.  S.  Geol.  Survey  Press 
Bull.  30,  Dec.  18,  1911. 

237 


238         CONTRIBUTIONS  TO  ECONOMIC   GEOLOGY,  1915,  PART  I. 

the  basis  of  the  present  report.  In  October,  1915,  during  the  first 
days  of  operation  of  the  Mineral  Products  Corporation,  the  region 
was  visited  by  H.  S.  Gale  and  V.  C.  Heikes,  of  the  United  States 
Geological  Survey.  Mr.  Gale's  description  of  properties  either  inac- 
cessible in  1914  or  developed  since  then  and  Mr.  Heikes's  description 
of  the  mill  are  incorporated  in  the  following  pages. 

The  known  alunite  deposits  in  Utah  are  in  Piute  County,  on  the 
east  side  of  the  Tushar  Mountains,  and  in  Beaver  County,  on  the  west 
side,  but  only  those  in  Piute  County  are  at  present  of  commercial 
importance.  The  deposits  of  Piute  County  are  from  7  to  8  miles 


FIGURE  13. — Index  map  showing  location  of  alunite  deposits  near  Marysvale  and  Beaver, 

Utah. 

southwest  of  Marysvale,  in  the  Ohio  and  Mount  Baldy  mining  dis- 
tricts, and  those  of  Beaver  County  are  about  10  miles  northeast  of 
Beaver,  in  the  Newton  mining  district.  (See  fig.  13.) 

Marysvale,  at  the  terminus  of  the  Marysvale  branch  of  the  Denver 
&  Rio  Grande  Railroad,  is  about  120  miles  south  of  the  main  line 
of  the  same  system.  Beaver  is  40  miles  southwest  of  Marysvale  and 
about  35  miles  east  of  Milf ord,  on  the  San  Pedro,  Los  Angeles  &  Salt 
Lake  Railroad, 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    239 
GEOLOGY  OF  THE  TUSHAR  MOUNTAINS.1 

The  Tushar  Mountains  form  part  of  a  long  north-south  range 
between  the  valley  of  Sevier  River  on  the  east  and  a  broad  desert  val- 
ley on  the  west.  The  floor  of  Sevier  Valley  near  Marysvale  has  an 
elevation  of  about  5,600  feet  and  that  of  Beaver  Creek  at  Milford 
about  5,450  feet.  From  these  depressions  the  mountains  rise  boldly, 
the  highest  summits  of  the  range,  situated  northwest  of  Marysvale, 
attaining  elevations  of  nearly  13,000  feet. 

The  range  is  composed  of  both  sedimentary  and  igneous  rocks.  It 
is  outlined  by  north-south  faults  and  is  thus  like  the  ranges  of  the 
Great  Basin  province  to  the  west.  However,  the  bedded  rocks, 
including  sediments  and  volcanic  flows,  are  not  greatly  tilted,  and  in 
this  respect  the  structure  is  like  that  of  the  plateau  province  to  the 
east. 

The  sedimentary  rocks  exposed  along  the  mountain  front  west  and 
southwest  of  Marysvale  comprise  limestones  and  quartzites  having 
an  aggregate  thickness  of  perhaps  2,000  feet.  These  formations  are 
regarded  as  of  Jurassic  age. 

Resting  on  the  eroded  surface  of  the  sedimentary  rocks  are  effusive 
volcanic  rocks  comprising  lava  flows  and  tuffs.  In  general  the  lower 
part  of  the  volcanic  series  is  composed  of  dacite,  but  chemical  inves- 
tigation may  show  that  some  andesite  also  is  present. 

Above  the  dacite,  forming  the  highest  part  of  the  range  and,  toward 
the  north,  extending  far  down  the  slopes,  is  a  series  of  light-colored 
rhyolite  flows  and  tuffs,  locally  called  shale.  Southeast  of  Beaver 
there  are  basalt  flowTs  that  are  younger  than  the  rhyolite.  The 
alunite  veins  of  the  region,  so  far  as  observed,  are  in  that  part  of  the 
volcanic  series  which  lies  below  the  rhyolite  flows. 

Of  later  origin  than  the  rhyolite  and  tuff  series  are  intrusive  rocks 
which,  though  of  diverse  composition,  are  all  related  to  quartz  mon- 
zonite.  These  rocks  occupy  relatively  small  areas,  but  the  mineral 
veins  of  the  region  are  later  than  them  and  are  undoubtedly  related 
to  them  genetically. 

The  Tushar  Range  is  delimited  on  the  east  and  west  by  prominent 
faults,  and  within  the  range  there  has  also  been  faulting  and  fissuring, 
which  have  affected  all  the  rocks  except  possibly  the  basalts.  In  the 
main  these  faults  within  the  mountains  show  northerly  to  north- 
westerly trends,  but  there  are  a  few  cross  breaks. 

The  mineral  deposits,  consisting  mostly  of  veins  but  including 
some  irregular  replacement  bodies,  conform  in  occurrence  with  the 
faulting  and  fissuring,  and  thus  most  of  them  show  northerly  to 
northwesterly  trends.  These  deposits  comprise  two  distinct  mineral- 
ogic  types,  one  containing  no  alunite  and  the  other  composed  almost 

1  This  description  is  summarized  from  U.  S.  Geol.  Survey  Bull.  511,  already  cited. 


240          CONTRIBUTIONS   TO   ECONOMIC   GEOLOGY,  1915,   PART   I. 

entirely  of  alunite  or  of  alunite  and  quartz.  In  general  the  alunite 
deposits  do  not  contain  sulphides  or  related  minerals  in  conspicuous 
amount,  whereas  the  other  veins  do,  and  some  of  them  have  been 
worked  for  metals,  principally  silver  and  gold.  Only  the  alunite 
deposits  were  examined  by  the  writer.  Those  southwest  of  Marys- 
vale  are  distinct  though  irregular  veins,  whose  formation  was  accom- 
panied by  a  minor  amount  of  replacement,  but  the  deposit  at  Sheep 
Rock,  northeast  of  Beaver,  is  an  irregular  replacement  body. 

ALUNITE  DEPOSITS    SOUTHWEST   OF  MARYSVALE. 

LOCATION  AND  EXTENT. 

The  best-known  alunite  deposits  southwest  of  Marysvale  are  in 
sees.  8,  16,  and  17,  T.  28  S.,  R.  4  W.     They  lie  in  three  roughly 


x  Alunite  in  place 
x  Tunnel 


oAlunite  float 
B  Shaft 


FIGURE  14. — Map  showing  location  of  prospects  in  the  principal  group  of  alunite  deposits 
near  Marysvale,  Utah.     Numbers  refer  to  descriptions  in  text. 

parallel  zones  of  northerly  to  northwesterly  trend,  the  eastern  and 
middle  zones  on  or  near  the  crests  of  ridges  near  the  headwaters  of 
Little  Cottonwood  Creek  and  its  North  Fork,  the  western  zone  close 


ALUNITE  DEVELOPMENTS  NEAR  MAEYSVALE  AND  BEAVER,  UTAH.    241 

to  the  bed  on  the  main  stream.  (See  fig.  14.)  The  prospects  along 
the  main  stream  can  be  reached  directly  by  a  circuitous  wagon  road, 
with  an  ascent  of  about  5,000  feet.  Prospects  east  of  the  creek 
(main  fork)  can  be  connected  by  short  inclined  tramways  with  this 
wagon  road,  or  by  long  tramways,  like  that  of  the  Mineral  Products 
Corporation,  extending  to  roads  nearer  Marysvale. 

Other  deposits,  only  little  prospected  in  1914,  lie  east  and  south 
of  those  just  mentioned.  The  prospects  on  the  Lost  Horse  and  Mo- 
hawk group  of  claims  are  about  2  miles  farther  from  Marysvale 
than  those  on  the  three  main  zones,  and  are  reached  by  trail  from 
the  Little  Cottonwood  Canyon  road.  Still  others  have  been  re- 
ported to  lie  south  of  the  divide  between  Little  Cottonwood  and 
Tenmile  canyons. 

CHARACTER. 
GENERAL  FEATURES. 

All  the  deposits  thus  far  found  are  doubtless  veins  cutting  por- 
phyry (altered  dacite),  though  in  only  a  few  exposures  have  their 
true  thicknesses  and  exact  trends  been  determined.  The  alignment 
of  prospect  pits  and  trenches  and  the  distribution  of  float,  however, 
indicate  for  the  most  part  trends  of  N.  20°-40°  W.,  though  at  a  few 
openings  the  trend  is  nearly  due  north.  The  dips  of  the  different 
veins  are  for  the  most  part  50°-TO°  W.,  but  vertical  dips  have  been 
noted  at  a  few  places  and  a  steep  easterly  dip  was  recorded  at  one 
obscure  exposure.  None  of  the  veins  have  been  opened  continuously 
along  their  strike,  but  the  alignment  of  openings  indicates  probable 
lengths  of  500  to  800  feet  for  continuous  veins  and  of  1,500  to  5,000 
feet  for  vein  zones.  The  widths  of  the  veins  or  vein  zones  are  con- 
siderable, but  the  prospect  trenches  on  all  but  the  Custer  vein  did 
not,  as  a  rule,  afford  a  satisfactory  estimate  of  the  width  or  thickness. 
The  Custer  vein  contains  an  average  thickness  of  about  10  feet  of 
high-grade  alunite,  on  each  side  of  wrhich  smaller  veins  or  bands  of 
alunite  alternate  with  similar  thicknesses  of  quartz  or  highly  silici- 
fied  porphyry. 

The  best  exposure  in  the  western  zone  is  on  the  L.  &  N.  No.  4  claim 
and  shows  an  exposed  thickness  of  26  feet,  of  which  20J  feet  is  high- 
grade  alunite  and  5-|  feet  quartz.  Other  openings  show  thicknesses 
of  8  to  20  feet.  The  veins  are  distinctly  banded,  bands  of  nearly  pure 
alunite  alternating  with  bands  of  quartz.  The  alunite  portions  them- 
selves are  for  the  most  part  banded  by  parallel  to  concentric  mark- 
ings similar  to  those  in  travertine,  or  "onyx  marble,"  and  char- 
acteristic of  open  fissure  fillings,  but  there  is  also  evidence  of  replace- 
ment on  a  minor  scale.  The  general  distribution  of  the  veins  is 
indicated  on  the  surface  by  elongate  to  irregular  areas  of  silicifica- 
14031°— 15 2 


242         CONTRIBUTIONS  TO  ECONOMIC   GEOLOGY,  1915,  PART  I. 

tion,  many  of  which  appear  to  have  determined  the  positions  of 
ridges  and  prominent  peaks  through  their  superior  resistance  to 
erosion. 

Three  varieties  of  alunite  have  been  noted  in  the  veins — coarsely 
crystalline,  fine  grained  to  dense,  and  laminated.  The  coarsely 
crystalline  variety  is  by  far  the  most  common.  It  is  pink  to  reddish, 
and  forms  large  masses  of  columnar  to  platy  crystals  as  well  as  small 
veinlets  that  cut  the  other  two  varieties.  It  is  practically  pure  but 
contains  minute  quantities  of  pyrite  or  limonite  and  silica  (chalced- 
ony and  opal).  It  is  most  readily  recognized  in  the  field  by  these 
properties,  together  with  its  high  specific  gravity  (about  2.82 1), 
which  is  distinctly  higher  than  that  of  calcite  (2.71),  the  only  min- 
eral in  the  region  that  is  likely  to  resemble  it  in  crystalline  form. 

The  fine-grained  variety  is  pink  to  white  and  resembles  porcelain 
where  hard  and  chalk  where  softened  by  weathering.  Under  the 
microscope  some  specimens  are  seen  to  consist  almost  entirely  of 
minute  crystals  of  alunite  with  only  an  apparently  negligible  amount 
of  pyrite,  silica,  and  kaolin;  but  in  other  specimens  these  impuri- 
ties are  more  conspicuous.  The  fine-grained  variety  may  resemble 
kaolin,  or  miner's  "talc,"  especially  if  enough  kaolin  is  present 
to  yield  its  characteristic  odor ;  but  the  fine-grained  alunite,  like  the 
coarse-grained  variety,  may  be  recognized  by  its  high  specific  gravity. 

The  laminated  or  shaly  variety  differs  from  the  fine-grained 
variety  only  in  its  structure,  which  is  evidently  due  to  shearing 
along  the  plane  of  the  vein.  Such  a  structure  could  have  been 
developed  in  either  of  the  other  varieties. 

DETAILED    DESCRIPTIONS. 

The  following  detailed  descriptions  of  the  alunite,  associated 
quartz,  and  altered  wall  rock  are  given  for  the  benefit  of  those 
especially  interested  in  the  mineralogy  and  genesis  of  the  veins : 

ALUNITE, 

In  the  coarsely  crystalline  variety  of  alunite  the  crystals  have  a  tubular 
form  and  occur  in  diverging  columnar  aggregates  crossed  by  parallel  lines  or 
bands.  In  some  places  the  larger  crystals  extend  across  these  bands ;  in  others 
the  bands  mark  either  interruptions  or  possibly  sealed  fractures.  The  diverg- 
ing character  of  the  crystal  aggregates  is  even  more  noticeable  under  the  mi- 
croscope than  in  hand  specimens.  The  rhombohedral  faces  of  the  crystals  are 
not  usually  well  developed,  but  in  many  places  an  open  cavity  between  two 
bands  shows  well-developed  rhombohedral  faces,  which,  however,  have  com- 
monly been  etched  by  later  solution.  What  in  the  hand  specimen  appear  to  be 
crystals  are  seen  under  the  microscope  to  be  composed  of  numerous  smaller 
crystals  diverging  from  a  central  axis,  forming  a  striking  plumose  structure. 

1This  figure  is  near  the  average  of  several  determinations  of  Marysvale  alunite  by 
W.  T.  Schaller,  of  the  United  States  Geological  Survey.  According  to  Dana's  Text- 
book of  mineralogy  (edition  of  1900,  p.  537)  the  specific  gravity  is  2.58  to  2.75. 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    243 

The  linos  marking  the  separation  of  the  bands  forming  the  vein  are  seen 
under  the  microscope  to  consist  of  narrow  hands  of  finely  crystalline  material 
of  various  orientation,  ^'here  the  larger  crystals  or  aggregates  cross  these 
lines  without  change  in  orientation,  they  give  the  impression  that  the  fine 
material  has  been  deposited  in  fractures  breaking  across  the  crystals.  It  is 
more  probable,  however,  that  a  slight  change  in  conditions  interrupted  deposi- 
tion or  altered  its  rate  and  caused  the  deposition  of  several  minute  unoriented 
crystals  instead  of  the  large  crystals,  after  which  a  return  of  the  original  con- 
ditions permitted  the  largest  crystals  to  continue  their  growth,  while  crystalli- 
zation in  part  began  at  new  centers.  Some  of  the  lines  are  due  to  a  change  in 
color  without  change  in  crystal  character  and  are  to  be  attributed  to  slight 
changes  in  the  composition  of  the  depositing  solution,  such  as  the  presence  or 
absence  of  a  trace  of  iron  oxide.  Parallel  wavy  or  concentric  bands  of  this 
type  are  very  common  in  cavern  deposits  such  as  stalactites,  stalagmites,  and 
crusts  lining  cave  and  fissure  walls,  and  their  presence  in  the  alunite  veins 
is  regarded  as  proof  that  this  variety  of  alunite  was  deposited  as  an  open-fissure 
filling.  Cavities  between  banded  aggregates  pointed  toward  each  other  mark 
places  where  the  openings  were  not  entirely  filled. 

The  lines  that  mark  the  boundaries  between  crystal  aggregates  growing  away 
from  each  other  require  a  different  explanation.  There  must  have  been  a  sur- 
face or  narrow  strip  of  material  on  which  the  aggregates  began  to  grow  but 
which  is  no  longer  present.  It  is  suggested,  from  evidence  presented  in  a  sub- 
sequent paragraph,  that  there  was  formerly  present  a  narrow  strip  or  sheet 
of  the  fine-grained  alunite,  which  has  since  disappeared  by  recrystallization 
into  the  coarsely  crystalline  variety. 

As  seen  under  a  low  power  of  the  microscope  the  coarsely  crystalline  variety 
appears  to  be  almost  pure,  but  when  it  is  studied  under  high  power  numerous 
yellow  globular  masses  are  revealed,  most  abundantly  between  the  crystals  or 
along  minute  fractures.  These  masses  are  probably  limonite.  Some  small 
spaces  and  also  certain  lines  of  zonal  growth  across  the  crystals  are  filled  or 
marked  by  cloudy  material,  some  of  which  looks  like  kaolin,  some  like  minute 
cubes  of  pyrite,  and  some  like  minute  bubble  inclusions,  while  much  of  it  is 
in  specks  too  small  to  warrant  even  a  suggestion  as  to  their  character.  A  few 
minute  crystals  of  undoubted  pyrite  are  present  in  the  alunite.  It  also  includes 
numerous  irregular  microscopic  masses  of  an  undetermined  mineral  that  appears 
to  be  isotropic  and  has  an  index  of  refraction  below  that  of  alunite.  Some 
of  these  masses  may  be  opal ;  others  of  similar  appearance  in  ordinary  light 
prove  between  cross  nicols  to  be  doubly  refracting  aggregates  with  a  bire- 
fringence like  that  of  quartz. 

In  one  specimen  from  the  mouth  of  the  tunnel  on  the  L.  &  N.  No.  4  claim  of 
the  Florence  Mining  &  Milling  Co.  the  casts  of  several  crystals  of  a  tetragonal 
or  orthorhombic  mineral  are  present  in  coarsely  crystalline  alunite.  The  casts 
are  as  much  as  half  an  inch  in  length,  about  a  millimeter  in  width,  and  square 
to  diamond  shaped  in  cross  section.  They  are  fringed  by  rows  of  alunite 
crystals  growing  normal  to  the  edges  of  the  casts  and  are  partly  filled  with  a 
brown  powder,  shown  under  the  microscope  to  consist  of  an  indeterminate 
amorphous  material  stained  with  brown  iron  oxide  and  containing  scattered 
crystals  of  alunite.  The  crystal  outline  and  mineral  association  suggest  that 
the  original  mineral  may  have  been  diaspore. 

The  fine-grained,  porcelain-like  variety  is  seen  under  the  microscope  to  be  a 
granular  mass  composed  of  irregular  crystals  of  alunite.  No  distinct  grains 
of  quartz  were  recognized  in  the  few  thin  sections  studied,  although  the  only 
analysis  of  this  variety  shows  the  presence  of  5.28  per  cent  silica.  In  some 


244          CONTRIBUTIONS   TO   ECONOMIC   GEOLOGY,  1915,   PART  I. 

thin  sections  distinct  though  minute  grains  of  pyrite,  partly  or  wholly  oxidized 
to  limonite,  are  thinly  scattered  through  the  alunite  mass.  The  fine-grained 
•variety  in  part  forms  thin  bands  between  uniformly  oriented  bands  of  the 
coarsely  crystalline  variety  but  for  the  most  part  is  cut  by  parallel  and  linked 
veinlets  of  the  coarsely  crystalline  alunite. 

Where  the  fine-grained  material  alternates  with  uniformly  oriented  bands  of 
the  coarse-grained  material  it  probably  represents  changes  in  conditions  of 
crystallization  in  an  open  fissure;  where  it  is  cut  by  veinlets  of  the  coarse- 
grained alunite  it  was  undoubtedly  the  first  to  form,  and  the  veinlets  were 
probably  in  part  derived  from  it.  Both  megascopic  and  microscopic  study  of 
the  latter  phase  show  that  the  coarse  crystals  in  these  veinlets  have  formed  in 
part,  if  not  wholly,  by  recrystallization  of  the  fine-grained  mass,  single  large 
crystals  growing  at  the  expense  of  many  small  ones.  Lenticular  patches  of  the 
fine-grained  type  inclosed  between  coarse-grained  veinlets  diminish  to  mere  lines 
between  bands  of  crystals,  and  large  crystals  project  into  the  fine-grained 
aggregates  or  may  even  inclose  a  few  fine  crystals  just  within  their  boundaries. 
So  far  as  microscopic  data  are  concerned,  this  process  is  one  of  simple  recrystal- 
lization. The  minute  pyrite  grains  in  the  fine  variety  are  no  more  than  enough 
to  account  for  the  dusty  patches  and  zonal  groups,  some  of  which  are  pyrite 
or  limonite,  in  the  coarse  crystals.  Silica  is  too  scarce  in  either  variety,  so  far 
as  seen  under  the  microscope,  to  be  of  much  significance  in  this  connection. 
The  small  amount  noted  in  the  coarsely  crystalline  variety  was  formed  either 
at  the  same  time  as  the  alunite  crystals  or  slightly  later  and  may  represent  a 
small  amount  of  submicroscopic  silica  in  the  fine-grained  type.  Further  col- 
lection and  study  of  impure  phases  of  the  fine-grained  type  are  needed  to  throw 
definite  light  on  this  question. 

No  distinct  transition  between  the  fine-grained  alunite  and  the  silicified  and 
alunitized  wall  rock  was  noted  in  the  exposures  of  rock  in  place.  Coarsely 
crystalline  alunite  was  found  in  direct  contact  with  silicified  rock,  both  at  the 
walls  and  within  the  veins.  Loose  fragments,  however,  along  some  of  the  pros- 
pect trenches  consist  of  rather  highly  alunitized  material  which  still  preserves 
more  or  less  distinctly  the  porphyritic  texture  of  the  local  wall  rock.  This 
evidence  suggests  that  there  may  be  a  transition  between  practically  pure  fine- 
grained alunite  and  the  silicified  and  alunitized  wall  rock. 

The  shaly  or  schistose  variety  was  noted  only  at  exposures  in  and  just  north- 
west of  the  Gillan-Custer  claims.  It  is  microcrystalline  and  contains  numerous 
slickensided  partings,  which  indicate  a  strong  shearing  movement  along  the  vein. 
It  consists,  like  the  other  varieties,  of  almost  pure  alunite  in  which  there  are 
a  few  minute  crystals  of  pyrite  (or  limonite).  It  also  contains  veinlets  and 
small  vugs  of  coarsely  crystalline  alunite,  so  arranged  as  to  leave  little  doubt 
that  they  have  resulted  from  local  recrystallization  of  the  sheared  alunite 
where  small  fractures  made  conditions  favorable. 

QUARTZ. 

The  quartz  bands  that  alternate  with  those  of  alunite  have  been  noted  in  the 
western  vein  zone  (see  fig.  14)  and  in  the  Custer  or  eastern  zone.  Further 
developments  will  doubtless  prove  their  existence  in  the  middle  zone  as  well. 
The  bands  consist  of  dense  or  mi<Tocrystallim>  quartz  with  a  little  pyrite  in 
fine  grains.  In  places  they  show  a  faint  trace  of  porphyritic  texture,  suggest- 
ing replacement  of  porphyry  rather  than  open-fissure  filling.  In  the  western 
zone,  as  shown  on  page  249,  the  quart/  hands  occur  at  irregular  intervals 
throughout  the  width  of  the  vein;  in  the  Custer  or  eastern  zone  they  alter- 
nate with  smaller  veins  of  alunite  on  each  side  of  the  main  alunite  body.  The 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    245 

contrast  in  character  between  this  dense  form  of  quartz,  or  highly  silicified 
porphyry,  and  the  pure  crystalline  alunite  is  striking  and  not  satisfactorily 
explained  from  the  evidence  at  hand. 

WALL  ROCK. 

Alteration  of  the  wall  rock  along  the  alunite  veins  is  pronounced  and  extends 
for  many  feet  on  each  side.  The  altered  rock,  dacite  porphyry,  is  white  to  pale 
pinkish  where  not  stained  by  iron  oxides  and  of  dull  or  chalky  luster.  The 
original  porphyritic  texture  is  distinctly  preserved  and  is  especially  prominent 
on  iron-stained  surfaces,  where  the  iron  oxides  have  colored  the  groundmass 
but  not  the  phenocrysts.  The  principal  minerals  present  are  quartz,  alunite, 
and  pyrite,  with  small  amounts  of  limonite,  kaolin,  apatite,  and  zircon. 

The  alunite,  as  seen  in  thin  section,  occurs  principally  as  interlocking  aggre- 
gates of  lath-shaped  crystals,  either  pure  or  accompanied  by  some  secondary 
quartz,  replacing  feldspar  phenocrysts.  These,  as  suggested  by  their  outlines 
and  by  the  character  of  feldspar  phenocrysts  in  this  type  of  rock  in  general, 
were  probably  mostly  if  not  all  of  plagioclase,  the  soda-lime  feldspar.  Alunite 
also  forms  smaller  aggregates  and  single  crystals  scattered  through  the  ground- 
mass  but  hardly  in  great  enough  amount  to  represent  all  the  original  f eld- 
spathic  material  of  the  groundmass. 

The  quartz  occurs  as  original  phenocrysts  which  have  been  only  slightly, 
if  at  all,  affected  during  the  alteration  process.  The  only  suggestions  of  their 
alteration  are  where  alunite  laths  penetrate  their  edges  and  where  an  alunite 
lath  is  found  wholly  within  a  quartz  phenocryst.  The  penetrating  alunite 
laths  may  merely  represent  small  original  embay ments  of  the  phenocryst  by 
the  groundmass,  but  the  presence  of  an  alunite  lath  within  a  quartz  phenocryst 
suggests  that  the  quartz  may  have  been  to  a  slight  extent  replaceable  by  the 
alunite.  Quartz  in  very  minute  granular  aggregates  now  forms  the  greater 
part  of  the  groundmass  and  must  have  replaced  at  least  a  part  of  the  original 
material,  as  no  feldspar  of  any  kind  could  be  recognized.  The  groundmass  is 
clouded  by  a  very  fine  dust,  which  may  be  in  part  kaolin  but  is  probably  for 
the  most  part  minute  grains  of  pyrite  and  limonite.  A  few  small  veinlets  and 
irregular  aggregates  of  secondary  quartz  are  present,  and  some  of  them  contain 
a  few  laths  of  alunite  which  evidently  grew  at  the  same  time  as  the  quartz. 

The  presence  in  the  same  thin  section  of  a  parallel  growth  of  secondary 
quartz  and  alunite  and  of  primary  quartz  phenocrysts  penetrated  by  alunite 
appears  contradictory,  but  the  material  observed  is  so  scant  and  in  grains  so 
small  that  no  great  significance  can  be  attached  to  it. 

The  pyrite  forms  evenly  scattered  grains  as  much  as  1  millimeter  or  more  in 
diameter  and  constitutes  4  or  5  per  cent  of  the  rock.  It  is  equally  abundant  in 
association  with  the  alunite  aggregates  and  with  the  secondary  quartz  in  the 
groundmass,  and  it  crystallized  at  the  same  time  as  these  minerals.  The  promi- 
nence of  pyrite  in  the  wall  rock  is  in  marked  contrast  to  its  obscurity  in  the 
alunite  veins.  The  absence  of  the  black  silicates,  augite,  hornblende,  and  biotite, 
in  the  altered  wall  rock  is  also  noteworthy,  and  it  may  be  that  the  iron  origi- 
nally present  in  these  minerals  is  now  largely  contained  in  the  pyrite. 

Kaolin  is  present  in  varying  though  small  amounts,  probably  as  minute  specks 
closely  associated  with  alunite  in  the  replaced  feldspar  phenocrysts.  Its  pres- 
ence may  be  detected  by  the  rather  weak  but  characteristic  odor  of  the  moistened 
specimen.  Limonite  is  present  as  brown  surface  stains  and  varies  in  amount 
with  the  degree  of  oxidation  of  the  pyrite.  Small  apatite  and  zircon  crystals, 
unaffected  by  the  alteration  process,  are  rather  abundant  in  some  thin  sections. 


246         COKTRIBUTIONS  TO  ECONOMIC   GEOLOGY,  1915,  PAET  I. 

It  is  clear  from  these  data  that  the  magnesia,  lime,  and  soda  originally  in  the 
wall  rock  were  removed,  while  silica,  the  sulphide  and  sulphate  radicles,  and 
water  were  introduced.  Until  analyses  of  the  fresh  and  altered  rock  can  be 
compared  it  can  not  be  determined  whether  aluminum,  iron,  or  potassium  were 
added  or  remained  in  practically  their  original  amounts.  Furthermore, 
although  the  alunite  occurs  mostly  as  a  replacement  of  soda-lime  feldspar,  it  is 
not  known  whether  the  alunite  in  the  rock  is  the  pure  potassium  variety,  like 
that  in  the  veins,  or  the  sodic  variety.  In  either  case,  some  potassium  was  in- 
troduced into  the  feldspar  phenocrysts,  but  the  amount  originally  in  the  ground- 
mass  would  doubtless  have  been  enough  to  account  for  the  potassium  in  sodic 
alunite,  whereas  some  additional  supply  may  have  been  necessary  to  account  for 
potash  alunite,  especially  where  the  alunitization  of  the  porphyry  is  most 
pronounced. 

A  preliminary  examination  of  the  wall  rock  of  other  than  alunite  veins  in 
the  region  has  not  disclosed  the  presence  of  alunite,  though  a  more  thorough 
study  may  do  so.  It  may  be  noted,  however,  that  metallic  minerals  are  reported 
from  prospects,  now  inaccessible,  around  Edna  Peak  (locally  called  Edna 
Geyser),  where  alunitization  of  the  rock  is  pronounced. 

CHEMICAL  COMPOSITION". 

The  following  analyses  of  Marysvale  alunite,  which  are  all  at 
present  available,  show  the  character  of  the  coarsely  crystalline  and 
dense  white  varieties : 

Analyses  of  alunite  from  Marysvale  region,  Utah. 

Crude  alunite  from   fust  or  group." 


1 

2 

3 

\lumina  (  AljOs)   

37.18 

34.40 

37.0 

Ferric  oxide  (FejOs) 

Trace. 

Trac«. 

38  34 

36  54 

38  6 

Phosphoric  anhydride  (PjOo)         .          

.58 

.50 

Potash  (KzO) 

10  46 

9  71 

11  4 

Soda(NajO)                        

.33 

.56 

Water  above  105°  C  (H"2O  +  ) 

12.90 

13  08 

13  0 

Water  bolow  105°  C  (HjO     ) 

09 

H 

Silica  (SiO2)                                    .                .              

.22 

5  28 

100.10 

100.18 

100.0 

a  Copied 'from  U.  S.  Geol.  Survey  Bull.  511,  p.  8. 


1.  Selected  specimen  of  clear  pink,  subtransparent,  coarsely  granular  crystalline  alunite.    Supposedly 
best  material.    W.  T.  Schaller,  analyst. 

M'rimen  of  a  light-pink,  ver 
and  no  distinct  structure.    W.  T.  Schalle,  . 

3.  Theoretical  composition  according  to  Dana,  Textbook  of  mineralogy,  1900  edition,  p.  537. 


. 

2.  Soli'cti-d  sjM'rimen  of  a  light-pink,  very  finely  granular  rock,  of  almost  porcelain-like  conchoidal  fracture 
.  T.  Schaller,  anuiyst  . 


Coarsely    crystalline    alunite    from    Florence    Mining    &   Milling    Co.'s    claims. 


4 

5 

Loss  on  ignit  ion 

42.8 

42  1 

Insoluble  residue  (alumina  with  perhaps  a  little  silica)  

39.3 

37.6 

Potassium  sulphate  (K?S  04)            

16.8 

18.5 

Equivalent  potash  (KjO) 

9  1 

10.0 

4.  1,000-pound  sample  from  Sunshine  Fraction  claim. 

5.  1,000-pound  sample  from  North  Fork  claim. 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    247 

Calcined  alunite. 

[Said  to  represent  the  average  of  the  coarsely  crystalline  alunite  used  in  analyses  4  and  5.    Determined 
by  fusion  with  sodium  carbonate.] 


4a 

5a 

Silica  (SiO2)     

0.03 
61.1 
1.6 
19.0 
17.2 
None. 
.29 

0.72 
61.1 
1.1 
18.1 
18.6 
None. 
.31 

Alumina  (  A12O3)  

Ferric  oxide  (  FejOs"*  

Sulphuric  anhydride  (SOs) 

Potassa(K2O)  

Lime  (CaO)                                                                                            

Magnesia  (MgO) 

99.22 

99.93 

[The  same  material  determined  by  leaching.] 


4b 

5b 

Insoluble  residue 

61.8 

62.2 

Potassium  sulphate  (KoSO4)                                                                          

32.6 

32.0 

Aluminum  sulphate  (AlaCSO^s) 

4.4 

5.0 

98.8 

99.2 

4  and  5,  4a  and  5a,  4b  and  5b  made  by  Solvay  Process  Co.  for  Florence  Mining  &  Milling  Co. 

Comparison  of  analyses  4  and  5  with  No.  1  shows  that  the  coarsely 
crystalline  alunite  in  the  prospects  on  the  Sunshine  Fraction  and 
North  Fork  claims  (Nos.  11  and  14,  respectively,  in  fig.  14),  south 
and  southeast  of  Edna  Peak,  is  practically  identical  in  composition 
with  that  in  the  Gillan-Custer  prospects  and  is  almost  entirely  free 
from  impurities.  Microscopic  examinations  of  coarsely  crystalline 
alunite  from  prospects  west  of  Edna  Peak  indicate  a  similar  degree 
of  purity.  Material  of  this  quality  is  fit  for  the  extraction  of  both 
potash  salts  and  alumina,  as  well  as  for  the  manufacture  of  alum  and 
for  use  as  fertilizer. 

Analysis  2  shows  that  the  fine-grained  variety  contains  a  consider- 
able amount  (5.28  per  ^ent)  of  silica.  More  analyses  of  material  of 
this  type  would  doubtless  show  some  variation  in  silica  content.  An 
amount  of  silica  as  great  as  5  per  cent  is  sufficient  to  increase  con- 
siderably the  cost  of  extraction  of  alumina  in  a  form  sufficiently  pure 
to  be  used  in  the  manufacture  of  metallic  aluminum — so  much,  per- 
haps, as  to  render  it  unprofitable — but  it  does  not  unfit  the  material 
for  the  manufacture  of  alum  or  for  use  as  fertilizer. 

Recalculation  of  analysis  1  shows  it  to  contain  92.74  per  cent  of  the 
potash  alunite  molecule  (K2O.3A12O3.4SO3.6H2O).  The  amount  of 
soda  present  is  equivalent  to  3.98  per  cent  of  soda  alunite,  but  the 
total  water  in  excess  of  that  required  by  the  potash  alunite  is  not 
enough  to  satisfy  this  amount.  Alumina  in  excess  of  the  amount  re- 
quired by  the  total  alunite  amounts  to  1.43  per  cent,  and  the  corre- 
sponding excess  of  the  sulphate  radicle  is  0.88  per  cent.  Some  of  this 


248         CONTRIBUTIONS   TO   ECONOMIC   GEOLOGY,  1915,  PAKT  I. 

alumina  may  be  combined  with  the  sulphate,  some  with  the  phosphate 
radicle,  and  some  with  silica,  but  nearly  or  quite  all  such  natural 
compounds  contain  water,  which  according  to  the  analysis  is  not 
present.  The  silica,  furthermore,  is  believed  to  represent  the  small 
amounts  of  quartz  and  opal  noted  under  the  microscope. 

Recalculation  of  analysis  2  shows  it  to  contain  85.28  per  cent  of  the 
potash  alunite  molecule  and  5.57  per  cent  of  the  soda  alunite  mole- 
cule, with  excesses  of  0.71  per  cent  of  alumina,  1.36  per  cent  of  the 
sulphate  radicle,  and  0.04  per  cent  of  total  water.  The  deficiency  of 
water  again  precludes  the  expression  of  these  excesses  as  natural 
minerals.  The  predominance  of  excess  sulphate  radicle  in  analysis  2 
is  in  contrast  to  the  predominance  of  excess  alumina  in  analysis  1, 
and  the  discrepancy  also  indicates  that  these  materials  are  not  present 
as  definite  compounds  but  are  probably  occluded  in  the  alunite.  The 
silica  in  analysis  2  is  greatly  in  excess  of  that  required  to  form  kaolin 
with  the  excess  alumina  and  doubtless  represents  one  or  more  varieties 
of  free  silica. 

PROSPECTS. 
PRINCIPAL    GROUPS. 

The  principal  groups  of  alunite  prospects  lie  in  three  roughly 
parallel  zones  of  northerly  to  northwesterly  trend.  (See  fig.  14, 
p.  240.)  The  western  and  middle  zones  are  within  the  property  con- 
trolled by  the  Florence  Mining  &  Milling  Co.,  whose  headquarters 
are  at  Philadelphia,  Pa.,  but  it  is  reported  that  some  of  the  claims 
along  the  western  zone  have  been  relocated  in  1915,  and  their  owner- 
ship is  at  present  in  doubt.  The  eastern  zone  has  its  north  end 
within  the  southeast  corner  of  the  same  property  but  lies  for  the 
most  part  within  the  Gillan-Custer  group  of  claims,  which  belong 
to  the  Mineral  Products  Co.,  of  Chicago,  111.,  and  is  operated  by  the 
Mineral  Products  Corporation,  of  Marysvale,  Utah. 

WESTERN    ZONE. 

The  western  zone  trends  northwestward  and  roughly  parallels  the 
north  headwater  branch  of  Little  Cottonwood  Creek.  Alunite  has 
been  exposed  at  a  number  of  places  in  this  zone.  Near  the  Little 
Cottonwood  Canyon  and  Bullion  Canyon  divide,  on  the  L.  &  N. 
No.  4  claim,  a  vein  striking  N.  40°  W.  and  dipping  about  40°  W.  is 
exposed  for  a  distance  of  40  feet  along  a  N.  25°  E.  trench  (No.  I1) 
and  for  (U)  feet  along  a  N.  70°  W.  tunnel.2  The  tunnel  portal  and 
the  north  end  of  the  trench  are  at  the  northeast  wall  of  the  vein, 

1  Numbers  in  parentheses  correspond  to  numbers  !n  figure  14  (p.  240). 

2  It  Is  reported  that  since  the  writer's  visit  this  tunnel  has  been  extended  for  100  feot 
along  the  vein  and  is  in  alunite  all  the  way.     (Oral  communication  by  W.  A.  Fitzpatrick, 
Florence  Mining  &  Milling  Co.)y 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    249 

but  the  southwest  wall  has  not  been  found.  The  true  width  at  this 
place  is  therefore  not  known  but  is  at  least  35  feet,  and  the  corre- 
sponding true  thickness  is  at  least  25  feet.  The  following  section, 
made  along  the  trench,  shows  that  the  vein  contains  at  this  place 
about  SO  per  cent  of  high-grade  alunite,  the  true  thickness  being  2QJ 
feet  of  alunite  and  5^  feet  of  quartz. 

Section  alomj  trench  at  locality  No.  1. 

Northeast  wall  of  alunitized  and  pyritized  porphyry.  Feet. 

Coarse  crystalline  alunite 2J 

Quartz 2 

Coar.so  crystalline  alunite 1 

Quartz  _1 3 

Coarse  crystalline  alunite 9£ 

Quartz \ 

Coarse  crystalline  aluuite 7£ 

26 

The  alunite,  quartz,  and  wall  rock  are  typical  and  need  no  further 
description. 

At  80  feet  northwest  of  the  tunnel  portal  float  of  alunitized  por- 
phyry and  some  well-crystallized  alunite  are  exposed  in  a  line  of 
shallow  trenches.  Farther  northwest,  on  the  crest  of  the  divide, 
alunite  fragments  are  exposed  in  a  small  cut  (No.  2).  These  occur- 
rences suggest  a  forking  of  the  vein  or  two  or  three  parallel  veins. 
Just  north  of  the  crest  of  the  ridge  and  about  250  feet  northeast  of 
the  cut  last  mentioned  are  two  shallow  cuts  (No.  3), exposing  alunite, 
which  appears  to  be  a  vein  of  northwesterly  trend,  8  feet  wide. 

Southeast  of  the  tunnel  alunite,  mostly  in  loose  fragments,  has 
been  exposed  in  three  shallow  trenches,  the  southeasternmost  of 
which  (Xo.  4)  lies  about  650  feet  from  the  tunnel.  An  old  shaft 
dump  (No.  5)  just  northeast  of  the  middle  trench  and  400  feet  from 
the  tunnel  consists  largely  of  alunitized  rock.  At  none  of  these 
places  has  sufficient  work  been  done  to  show  the  direction  and  width 
of  the  vein  or  its  percentage  of  high-grade  alunite.  The  position 
of  the  vein  at  the  tunnel  suggests  either  that  the  southeasternmost 
of  the  three  cuts  may  represent  a  parallel  vein,  or  that  the  vein  has 
been  offset  by  faulting. 

The  next  exposure  of  alunite  to  the  southeast  is  an  outcrop  (No.  6) 
close  to  the  east  bank  of  the  creek,  1,500  feet  from  the  cut  last  men- 
tioned, and  in  line  with  the  strike  of  the  vein  exposed  in  the  tunnel. 
From  500  to  1,000  feet  farther  south  alunite  and  alunitized  rock 
have  been  exposed  in  a  group  of  small  cuts  and  in  two  short  tunnels 
(No.  7).  Alunite  float  has  been  reported  along  the  east  side  of  the 
creek  for  the  next  1,500  feet  southeastward  (Nos.  8  and  9),  but  little 
or  no  development  work  had  been  done  on  it  up  to  the  fall  of  1914. 
14031°— 15 3 


250          CONTRIBUTIONS   TO   ECONOMIC    GEOLOGY,   1915,   PART   I. 

MIDDLE    ZONE. 

The  middle  zone  extends  along  the  crest  of  the  ridge  which  divides 
the  North  Fork  from  Little  Cottonwood  Creek.  Alunite  has  been 
traced  in  this  zone  from  Edna  Peak  southward  to  the  fork  of  the 
ridge  but  has  been  prospected  thus  far  only  by  shallow  trenches. 

At  Edna  Peak  alunite  has  been  found  both  on  the  northwest  and 
southeast  slopes.  Only  one  vein,  that  on  the  southeast  slope  of  the 
peak,  has  been  traced,  and  no  work  has  been  done  to  determine 
whether  the  exposure  on  the  northwest  slope  is  a  branch  of  the  same 
vein  or  is  a  parallel  vein  which  pinches  out  toward  the  south.  About 
900  feet  south  of  Edna  Peak  the  alunite  vein,  which  strikes  N.  15° 
E.  and  dips  steeply  to  the  east,  is  shown  in  a  trench  (No.  10)  to  have 
a  width  of  over  15  feet,  but  neither  wall  is  exposed.  Farther  south 
it  is  partly  exposed  in  five  trenches  (No.  11)  and  has  an  average  dip 
of  about  50°  W.  The  length  exposed  by  the  six  trenches  is  about 
650  feet ;  the  length  from  Edna  Peak  to  the  southernmost  of  these 
trenches  is  about  1,550  feet.  Beyond  the  southernmost  trench  the 
vein  appears  to  have  stopped  abruptly,  but  the  surface  is  so  thickly 
covered  by  loose  rock  that  it  is  impossible  to  determine  on  the  sur- 
face whether  the  vein  pinches  out  or  is  cut  off  by  a  fault,  as  sug- 
gested in  figure  14.  Nearly  400  feet  farther  south  and  a  little  east 
of  the  course  of  the  vein  a  small  amount  of  alunite  has  been  exposed 
in  three  shallow  trenches  (No.  12),  but  not  enough  work  has  been 
done  here  to  demonstrate  the  size  of  the  vein.  The  abundance  of 
alunite  float  down  the  slope  east  of  these  trenches  suggests  that  the 
strongest  vein  at  this  place  has  not  been  uncovered.  No  further 
excavations  have  been  made  to  test  the  southward  extent  of  this 
zone.  A  partial  analysis  of  coarsely  crystalline  alunite  from  this 
vein,  on  the  Sunshine  Fraction  claim,  is  given  in  column  4  of  the 
table  on  page  246. 

EASTERN   ZONE. 

The  eastern  zone  includes  three  distinct  groups  of  exposures  and 
probably  three  or  more  veins.  It  has  been  prospected  on  the  spur 
southwest  of  the  North  Fork  of  Little  Cottonwood  Creek,  as  shown 
in  figure  14.  The  prospects  farthest  to  the  northwest  include  three 
pits  on  the  ground  of  the  Florence  Mining  &  Milling  Co.  The  west- 
ern pit  (No.  13)  exposes  alunite,  which  is  also  represented  by  float 
on  the  knob  directly  to  the  south.  About  200  feet  due  east  of  this  pit 
are  two  shallow  trenches  (No.  14)  mostly  in  loose  fragments  of 
alunite  and  altered  rock  but  also  exposing  high-grade  material  in 
place.  The  strike  of  the  vein  here  is  N.  5°  E.,  and  the  exposed  width 
-of  hiirli-.irnule  alunite  is  15  feet.  The  strike  of  the  vein  proves  it  to 
be  distinct  from  the  alunite  exposed  to  the  west.  A  partial  chemical 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    251 

analysis  of  the  alunite  is  given  on  page  246,  column  5,  and  agrees 
closely  with  the  other  analyses  of  high-grade  alunite. 

The  remaining  exposures  in  the  eastern  zone  are  in  the  prospects 
on  the  property  of  the  Mineral  Products  Corporation,  as  shown  in 
figure  14.  These  were  the  only  developments  in  1911,  when  the  data 
for  Survey  Bulletin  511  were  collected.  Since  then  considerable 
work  has  been  done  on  this  property.  It  was  idle  when  visited  in 
1914  but  was  examined  in  October,  1915,  by  Mr.  Gale,  whose  descrip- 
tion of  the  newer  developments  is  as  follows : 

The  developments  on  the  Gillan-Custer  group  of  claims  have  been 
by  far  the  most  active.  They  have  included  the  opening  of  two 
principal  tunnels  in  the  effort  to  determine  the  extent  and  con- 
tinuity of  the  alunite  underground  and  the  sinking  of  numerous 
shallow  pits,  shafts,  and  tunnels  with  the  object  of  tracing  the  veins. 

The 'first  or  lower  tunnel  on  this  property  was  run  in  below  most 
of  the  surface  croppings  of  alunite,  in  an  effort  to  cut  the  main  vein 
at  depth.  For  a  time  it  seemed  as  if  the  vein  had  been  missed,  but  in 
the  final  developments  on  this  level  the  ore  was  found  and  followed 
for  some  distance  in  line  with  and  almost  directly  under  the  later 
development  in  an  upper  tunnel.  Work  at  this  level  was  discontinued 
pending  further  explorations  higher  up  and  nearer  the  outcrops. 

The  main  tunnel,  or  present  working  mine  (October,  1915),  is 
about  200  feet  higher  than  the  old  tunnel.  Its  portal  lies  just  about 
over  the  last  extension  of  the  lower  tunnel  in  the  line  of  the  vein. 
It  starts  on  an  exposure  of  massive  crystalline  alunite  which  trends 
about  N.  55°  W.  and  dips  about  75°  S.  as  measured  on  the  bands  of 
crustification  in  the  vein.  At  the  east  side  of  the  portal  is  siliceous 
wall  rock  containing  some  alunite  and  stained  rusty  red  so  that  in 
appearance  it  is  much  like  the  ore.  This  tunnel  was  driven  along 
the  ore  with  the  intention  of  following  the  footwall  side  but  passed 
through  several  breaks  or  offsets  whose  origin  and  relation  to  the 
ore  were  not  fully  indicated.  There  was  some  difficulty  in  follow- 
ing the  ore.  but  at  the  time  of  visit,  late  in  October,  1915,  the  vein  had 
again  been  picked  up  and  mining  and  developments  were  proceed- 
ing in  a  very  satisfactory  way.  These  developments  are  following 
directly  underneath  the  line  of  surface  cuts,  which  expose  wide  sec- 
tions of  the  alunite  vein,  as  described  in  Bulletin  511. 

The  underground  work  done  in  the  exploration  and  development 
of  this  property  has  disclosed  a  greater  irregularity  both  in  char- 
acter and  continuity  of  the  main  veins  than  was  expected  from  the 
larger  and  apparently  uniform  exposures  of  crystalline  alunite 
in  the  surface  cuts  above.  However,  it  appears  that  these  workings 
have  now  opened  an  ore  reserve  large  enough  to  insure  the  operation 
of  the  plant  for  some  time  and  that  there  is  a  good  prospect  of  run- 


252          CONTRIBUTIONS    TO   ECONOMIC    GEOLOGY,   1915,   PART   I. 

ning  into  a  larger  body  of  high-grade  ore  beyond,  where  the  surface 
exposures  above  are  complete  and  apparently  very  regular. 

It  has  not  been  satisfactorily  determined  whether  the  irregular- 
ities found  in  the  alunite  veins  are  due  to  faulting  or  offsets  of  the 
veins  since  their  formation,  or  whether  they  are  an  original  feature 
of  the  deposits.  A  number  of  fissures  encountered  in  the  present 
workings  are  filled  with  a  smooth  and  very  plastic  red  clay,  in  places 
containing  angular  fragments  of  the  wall  rocks.  Here  and  there, 
however,  the  original  crustification  in  the  main  alunite  vein  appears 
to  pass  these  clay  seams  without  offset.  Some  of  these  clay  seams 
are  accompanied  by  cross  veins  of  crystalline  alunite,  which  are 
evidently  secondary  to  the  main  deposit.  Owing  to  obscurity  of  the 
vein  walls  and  of  the  relations  at  the  points  where  discontinuity  of 
the  vein  has  been  found,  it  can  not  yet  be  stated  to  what  these  irregu- 
larities are  due,  although  doubtless  this  relation  will  become  clear 
as  mining  developments  proceed. 

The  mine  as  now  equipped  is  capable  of  supplying  150  to  200  tons 
of  milling  ore  a  day  and  its  capacity  can  be  increased. 

OTHER   PROSPECTS. 

Other  indications  and  prospects  thus  far  reported  lie  to  the  east 
and  south  of  the  zone  just  described.  The  following  notes  give  the 
only  available  information  on  them  at  the  time  of  writing : 

Iron  Blossom  group. — The  prospects  on  the  Iron  Blossom  group 
of  claims  have  not  been  seen  by  the  writer.  There  are  said  to  be 
two  occurrences  of  alunite  in  place,  one  on  each  slope  of  the  North 
Fork  canyon,  and  one  occurrence  of  alunite  float  between  them  close 
to  the  bed  of  the  creek.  The  deposit  on  the  southwest  slope  of  the 
canyon  is  near  those  at  the  northwest  end  of  the  Mineral  Products 
Corporation's  ground  and  evidently  belongs  to  the  same  vein  zone. 
The  other  occurrences  presumably  represent  two  additional  veins, 
but  no  definite  information  regarding  them  has  been  obtained. 

Gillarts  claims. — Alunite  has  recently  been  found  on  Tom  Gillan's 
claims  in  the  foothills  3  miles  southwest  of  Marysvale  and  three- 
fourths  of  a  mile  east  of  the  Deer  Trail  mine.  According  to  Mr. 
Gale,  the  alunite  occurs  in  veins  and  bunches  associated  with  a  silici- 
fied  zone  in  porphyry  of  the  same  character  as  that  which  forms  the 
country  rock  about  the  main  alunite  deposits  higher  up  in  the  moun- 
tains. Both  coarse  and  fine  grained  varieties  of  alunite  are  present, 
and  the  color  ranges  from  Avhite  through  yellow  to  pink.  Although 
there  are  some  large  blocks  of  high-grade  ore  at  this  locality,  the 
indications  of  an  ore  body  are  not  so  strongly  marked  by  float  as  at 
the  main  veins  of  the  district.  A  specimen  sent  to  the  writer  by 
Mr.  Heikes  consists  of  the  fine-grained  variety,  considerably  sheared 
and  accompanied  by  broken  stringers  of  quartz. 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    253 

Santa  Kruze  claims. — A  specimen  sent  by  A.  ,Soyka,  said  to  be 
from  the  Santa  Kruze  Xo.  4  claim,  4,000  feet  southeast  of  the 
Krotki  iron  mine,  was  u^Unl  at  the  Survey  laboratory  and  found 
to  be  alunite  of  good  quality.  This  district  doubtless  deserves 
investigation. 

Mohair  I'  </ro>ip. — The  Mohawk  group  is  located  on  the  north  side 
of  Mill  Fork  of  Little  Cottonwood  Creek,  nearly  due  south  of  the 
prospects  on  the  western  vein  zone.  According  to  Mr.  Gale,  new  de- 
velopments on  the  property  include  a  tunnel  and  a  shaft.  The  shaft 
at  the  time  of  his  visit  was  30  feet  deep,  and  in  a  short  crosscut  10 
feet  to  the  south  some  fine-grained  white  material  of  uncertain 
alunite  content  had  been  exposed.  Since  Mr.  Gale's  visit  it  has  been 
reported  that  the  shaft  had  been  sunk  to  a  depth  of  35  feet  and  had 
exposed  some  massive  alunite.  The  tunnel  was  being  driven  N.  14° 
TT.  to  reach  the  shaft  at  a  depth  of  200  feet  below  its  present  bottom. 

Lost  Horse  group. — The  Lost  Horse  group  of  claims  extends  along 
the  east  side  of  the  crest  of  the  range,  south  of  Mill  Fork  and  the 
Mohawk  group.  Alunite  has  been  found  in  place  at  two  prospects, 
and  float  has  been  followed  at  several  others.  These  places  lie  in  a 
nearly  north-south  zone  but  are  hardly  close  enough  together  to  be 
regarded  as  strong  indications  of  a  continuous  vein,  especially  when 
the  northwesterly  trends  of  the  vein  farther  north  (see  fig.  14)  are 
considered.  The  alunite  in  place  was  found  in  the  summer  of  1914  by 
trenching  into  a  slope  where  float  was  abundant,  but  not  enough 
work  was  done  to  determine  the  width  or  trend  of  the  vein.  The 
alunite  exposed  here  is  a  mixture  of  the  coarsely  crystalline  and  fine 
chalky  varieties,  the  coarse  material  forming  a  network  of  veins 
through  the  fine.  At  the  southernmost  occurrence  of  float,  on  the 
saddle  where  the  Beaver-Marysvale  trail  crosses  the  divide,  three 
or  four  short  trenches  have  been  dug,  exposing  a  considerable  amount 
of  the  chalky  variety,  a  small  part  of  which  is  stained  reddish  or 
brown.  The  other  float  occurrences  were  not  seen.  Xo  analyses  of 
alunite  samples  from  this  property  have  been  reported. 

ORIGIN  OF  THE  DEPOSITS. 

So  far  as  origin  of  the  alunite  veins  is  concerned,  the  evidence 
presented  in  the  preceding  pages  practically  confirms  the  statements 
of  Butler  and  Gale,1  that  the  veins  were  formed,  for  the  most  part,  in 
open  fissures  and,  in  addition,  suggests  that  a  part  of  the  fine-grained 
alunite  may  have  been  formed  as  a  replacement  of  porphyry.  In  this 
respect,  as  well  as  in  the  alteration  of  the  wall  rock,  the  mode  of 
deposition  was  similar  to  that  of  the  Sheep  Rock  deposit,  described  on 

1  U.  S.  Geol.  Survey  Bull.  511,  pp.  7,  20,  1912. 


254          CONTRIBUTIONS   TO   ECONOMIC    GEOLOGY,   1915,   PART   I. 

pages  258-264,  but  replacement  accounts  for  practically  all  the 
Sheep  Rock  deposit  instead  of  a  part  of  it.  Regarding  the  source 
of  the  alunite-forming  solutions,  no  evidence  has  been  found  at  vari- 
ance with  the  hypothesis  of  Butler,1  which  is  briefly  as  follows: 

During  and  just  subsequent  to  the  consolidation  of  the  intrusive 
masses  all  the  rocks  in  the  region,  both  sedimentary  and  igneous,  were 
fissured.  Along  these  fissures  ascended  heated  solutions  believed  to 
have  been  derived  from  the  intrusive  magma.  Within  the  intrusive 
mass  they  were  highly  heated,  probably  under  considerable  pres- 
sure, and  deposited  minerals  characteristic  of  this  condition.  As 
they  passed  into  the  cooler  overlying  rocks  both  temperature  and 
pressure  were  reduced,  and  the  valuable  metalliferous  veins  of  the 
region  were  deposited.  These  veins  were  formed  in  two  stages,  the 
earlier  one  characterized  by  carbonate  gangue  minerals  and  the  later 
by  quartz  and  adularia.  The  adularia  is  of  special  interest,  as  it  is  a 
pure  potassium-aluminum  silicate  and  indicates  a  certain  concentra- 
tion of  these  elements  during  the  later  stages  of  vein  deposition. 

The  alunite  veins  are  thought  to  represent  a  still  later  stage  of 
deposition,  characterized  by  a  much  higher  concentration  of  potassium 
and  aluminum  in  the  form  of  sulphate.  Structural  evidence  indicat- 
ing this  relation  of  the  alunite  to  the  metalliferous"  veins  is  not  yet 
complete.  The  relation  is,  however,  suggested  by  the  mode  of  occur- 
rence of  alunite  in  other  regions,  where  general  conditions  indicate 
that  the  mineral  was  deposited  at  shallow  depth  and  at  moderate  to 
low  temperature.  The  relative  rarity  of  alunite  deposits  compared 
with  quartz-adularia  veins  in  this  country  and  abroad  may  be  due  to 
the  fact  that  they  are  formed  near  the  surface  and  consequently  have 
in  only  a  few  places  been  preserved. 

According  to  this  interpretation,  it  is  to  be  expected  that  in  places 
alunite  veins  will  be  found  superimposed  on  quartz-adularia  veins. 
It  might  be  supposed  that  the  quartz  bands  which  alternate  with 
alunite  bands  in  several  exposures  represent  the  quartz-adularia 
stage  and  that  the  alunite  is  a  later  deposit  introduced  after  the 
quartz  vein  had  been  reopened  by  longitudinal  fracturing.  Such 
may  prove  to  be  the  relation  in  some  deposits,  but  no  quartz  bands  in 
the  veins  have  been  found  with  the  characteristic  hackly  structure  of 
the  quartz-adularia  veins,  and  microscopic  study  of  the  wall  rock 
shows  simultaneous  deposition  of  quartz,  alunite,  and  pyrite.  It  is 
more  probable,  therefore,  that  the  quartz  bands  were  formed  during 
the 'same  stage  of  deposition  as  the  alunite,  as  in  the  Sheep  Rock 
deposit  described  on  page  262. 

Where  alteration  along  the  quartz-adularia  veins  was  most  intense 
potassium  and  aluminum  were  nearly  or  quite  all  removed  from  the 

1  T*.  S.  Ool.  Survey  Bull.  511,  pp.  21,  38,  1912. 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    255 

wall  rock.  In  the  wall  rock  of  the  alunite  veins,  however,  alunite 
appears  to  be  sufficiently  abundant  to  account  for  all  the  potassium  of 
the  original  rock,  and  it  is  therefore  certain  that  the  rock  immediately 
adjacent  to  the  alunite  veins  did  not  supply  the  potassium  to  them  by 
lateral  secretion.  In  fact,  where  the  wall  rock  has  been  replaced  by 
the  fine-grained  alunite  there  must  have  been  a  considerable  addi- 
tion of  potassium  to  the  amount  already  present.  It  is  possible, 
however,  that  at  least  a  part  of  the  potassium  and  aluminum  con- 
tent of  the  vein  was  derived  from  the  wall  rock  at  greater  depth, 
where  conditions  were  favorable  to  the  leaching  of  these  elements,  and 
that  the  enriched  solutions,  rising  into  cooler  zones,  redeposited  them 
in  the  form  of  alunite.  This  interpretation  implies  that  the  alunite 
bodies  are  deposits  of  relatively  shallow  type  and  may  give  out  in 
depth  or  merge  into  a  different  type  of  vein.  The  fact  that,  although 
quartz-adularia  veins  are  of  common  occurrence  in  the  West,  no 
important  alunite  deposits  have  been  found  associated  with  them 
except  near  Marysvale  necessarily  leaves  this  idea  as  a  suggestion 
rather  than  a  conclusion. 

PERSISTENCE  IN  DEPTH. 

As  already  stated,  the  characteristic  features  of  alunite  deposits 
in  several  parts  of  the  world 1  indicate  deposition  at  shallow  depths. 
Recent  developments  at  Marysvale  on  all  but  the  Gillan-Custer  group 
of  claims  have  been  merely  superficial,  and  the  deepest  workings  on 
that  property  are  only  about  260  feet  below  the  lowest  outcrops  of 
alunite.  The  cautious  attitude  taken  by  Butler  and  Gale  regarding 
the  persistence  of  the  veins  in  depth  should  therefore  be  maintained. 

The  foreign  deposits  that  compare  most  closely  in  character  with 
the  alunite  veins  of  Marysvale  are  those  at  Tolfa,  Italy.  The  largest 
of  these  deposits,  the  Providenza  vein,  has  been  worked  to  a  depth 
of  more  than  300  feet,  where  it  becomes  increasingly  pyritic,  and  it 
ends  within  the  next  60  feet.  The  downward  continuation  of  the 
vein  zone  is  marked  by  pyritic  wall  rock  (trachyte).  That  in  gen- 
eral a  greater  vertical  range  than  that  of  the  Tolfa  deposits  can  be 
expected  in  the  alunite  veins  of  the  Marysvale  region  is  suggested  by 
the  observed  distribution  of  outcrops  with  reference  to  the  rugged 
topography.  In  the  eastern  zone  near  Marysvale  the  highest  out- 
crops according  to  Gale's  observations2  are  at  least  1,000  feet  above 
the  lowest;  in  the  middle  zone  the  observed  vertical  distribution, 
according  to  surveys  for  the  Florence  Mining  &  Milling  Co.,  is  about 
900  feet;  in  the  western  zone,  according  to  the  same  authority,  it  is 

1  Descriptions  of  these  deposits  are  reviewed  by  Butler  and  Gale   (U.   S.  Geol.  Survey 
Bull.  511,  pp.  38-58,  1912). 

2  Op.  cit,  pi.  3. 


256          CONTRIBUTIONS   TO    ECONOMIC    GEOLOGY,   1915,   PART   I. 

over  TOO  feet,  and  the  distribution  of  float  indicates  that  it  may  be 
considerably  more.  There  is  no  apparent  reason  why  the  actual 
range  in  depth  should  not  equal  or  considerably  exceed  these  amounts. 
It  should  be  borne  in  mind,  however,  that  the  alunite  deposits,  like 
many  metalliferous  deposits,  may  occur  in  shoots  with  a  distinct 
pitch,  and  that  their  lowest  parts  may  happen  to  be  along  a  line 
roughly  parallel  to  the  present  surface  slope.  In  this  case  the  shoots 
in  the  higher  parts  of  the  veins  may  possibly  end  downward  at  levels 
higher  than  those  of  the  present  lower  outcrops. 

SUGGESTIONS   REGARDING   DEVELOPMENT. 

Because  of  the  existing  uncertainty  in  regard  to  the  vertical  range 
of  the  deposits,  the  safest  method  of  prospecting  seems  to  be  the 
driving  of  tunnels  along  the  strike  of  the  vein  at  various  levels  and 
the  sinking  of  inclined  winzes  along  the  dip,  rather  than  the  driving 
of  tunnels  from  points  below  the  lowest  outcrops  with  the  hope  of 
tapping  the  veins  at  greater  depth.  The  eastern  and  western  zones 
of  the  principal  group  are  well  adapted  to  this  method  of  develop- 
ment. The  middle  zone,  located  on  the  crest  of  a  high  ridge,  could 
be  easily  worked  through  a  tunnel  cutting  the  vein  at  considerable 
depth,  provided  there  was  certainty  of  sufficient  continuity  and 
regularity  in  depth.  The  Franklin  tunnel  (see  fig.  11)  on  the 
Florence  Mining  &  Milling  Co.'s  ground,  driven  several  years  ago 
and  inaccessible  at  present,  is  excellently  situated  for  such  develop- 
ment. It  extends,  according  to  private  survey  records  of  this  com- 
pany, almost  directly  under  the  outcrops  on  Edna  Peak.  A  crosscut 
of  200  or  300  feet  should  cut  the  vein  zone  on  its  dip  at  a  depth  of 
1.000  feet  or  more  below  the  outcrops,  and  determine  whether  alunite 
in  commercial  quantity  extends  to  so  great  a  depth.  It  is  also  pos- 
sible that  examination  of  the  walls  of  the  tunnel  may  result  in  the 
discovery  of  one  or  more  additional  alunite  veins,  cut  long  before 
the  identity  and  possible  commercial  value  of  the  mineral  was  recog- 
nized. 

While  the  steam-shovel  method  may  be  satisfactory  for  the  removal 
of  thick  accumulations  of  debris  from  the  surfaces  of  the  veins, 
there  are  objections  to  its  use  in  the  direct  mining  of  alunite,  because 
a  considerable  amount  of  siliceous  impurity  will  thus  be  included 
in  the  high-grade  material.  This  lowering  of  the  grade  of  alunite 
may  not  be  sufficient  to  interfere  seriously  with  the  extraction  of 
potassium  sulphate,  or  with  the  use  of  the  insoluble  residue  in  the 
manufacture  of  refractory  brick,  or  with  the  use  of  crude  or  cal- 
cined alunite  as  a  fertilizer,  but  it  will  greatly  increase  the  cost  of 
the  manufacture  of  metallic  aluminum.  Furthermore,  the  pro- 
nounced western  dip  of  the  veins  would  involve  an  increasing  amount 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    257 

of  dead  work  in  the  removal  of  an  increasing  amount  of  waste  from 
the  hanging  wall  as  depth  increases. 

ESTIMATE  OF  TONNAGE. 

The  quantity  of  potash  (K2O)  available  in  the  Custer  vein  was 
estimated  by  Butler  and  Gale 1  at  30,000  tons  for  each  100  feet  of 
depth.  The  openings  seen  by  the  writer  along  the  middle  zone  do 
not  afford  sufficient  data  for  more  than  a  rough  estimate  of  the 
tonnage  of  alunite  available,  and  those  along  the  western  zone  and 
other  prospects  are  too  obscure  and  scattered  to  warrant  any  estimate. 
The  following  figures  are  intended  only  to  give  a  rough  idea  of  the 
quantity  of  alunite  within  the  limits  of  the  ground  actually  pros- 
pected. The  number  of  short  tons  for  each  foot  of  depth  is  calcu- 
lated by  assuming  a  specific  gravity  of  2.82,  or  a  weight  of  175 
pounds  a  cubic  foot.  These  are  the  figures  given  in  Bulletin  511,  on 
page  12.  The  alunite  in  the  exposures  represented  in  the  table  is 
practically  identical  with  that  used  for  the  determination  of  specific 
gravity. 

Estimated  tonnage  per  foot  of  depth  in  alunite  veins  in  middle  and  eastern  zones. 


Location. 

Proved 
length  of 
vein. 

Average 
width  of 
high-grade 
alunite. 

Surface 
area. 

Quantity 
of  alunite 
per  foot  of 
depth. 

Edna  Peak  to  No.  10  

Feet. 
900 

Feet. 
10 

Sq.fett. 
9,000 

Short  tons. 

788 

Openings  at  Nos.  10  and  11 

650 

10 

6,500 

698 

Openings  at  No.  14  

200 

15 

3,000 

263 

Gillan-Custer  group  (Butler  and  Gale's  estimate).  .  . 

3  000 

1,750 

18,500 

4  749 

If  the  recoverable  potash  (as  K2O)  is  estimated  at  10  per  cent, 
the  prospects  on  the  middle  zone  will  yield  about  17,000  tons  of 
potash  for  each  100  feet  of  depth,  somewhat  more  than  half  the 
amount  (30,000  tons)  similarly  estimated  by  Butler  and  Gale  for 
the  openings  on  the  Gillan-Custer  group.  Recent  underground 
developments  have  shown  that  the  Gillan-Custer  deposit  is  much 
more  irregular  than  was  indicated  by  the  surface  workings.  In 
some  places  high-grade  alunite  may  be  practically  absent,  and  in 
others  it  is  much  thicker  than  the  average  thickness  (10  feet) 
assumed  in  the  estimate;  but  the  estimate  will  doubtless  stand  as  a 
reasonable  and  satisfactory  minimum  of  workable  alunite  for  this 
group  of  claims.  Future  developments  on  the  middle  zone  may 
show  similar  irregularities,  and  the  figures  given  above  should  be 
regarded  as  representing  a  preliminary  moderate  estimate. 


1  Op.  cit.,  p.  12. 


£58         CONTRIBUTIONS   TO   ECONOMIC   GEOLOGY,  1915,  PART  I. 

It  should  be  borne  in  mind  that  only  those  openings  have  been 
included  in  the  estimate  where  the  practical  continuity  of  the  veins 
has  been  demonstrated  or  is  highly  probable.  Further  prospect- 
ing along  the  strikes  of  the  different  veins,  especially  that  exposed 
on  the  L.  &  N.  No.  4  claim,  in  the  western  zone,  will  probably  increase 
considerably  the  proved  tonnage  of  alunite.  According  to  the  above 
estimates,  the  tonnage  of  the  middle  and  eastern  zones  may,  for  each 
100  feet  of  depth,  amount  to  about  one-fourth  of  the  annual  con- 
sumption of  potash  in  the  United  States,  which,  figured  as  K2O, 
was  more  than  185,000  tons  in  1913,  the  latest  normal  year. 

DEPOSITS   ON  WEST   SLOPE  OF  MOUNTAINS. 

LOCALITIES. 

A  few  deposits  of  alunite  have  also  been  reported  from  the  west 
slope  of  the  Tushar  Mountains,  but  that  at  Sheep  Rock,  northeast 
of  Beaver  (see  fig.  13,  p.  238),  is  the  only  one  visited  by  the  writer 
and  the  only  one  from  which  specimens  containing  alunite  have  been 
seen  by  him.  One  deposit,  about  2J  miles  southeast  of  the  Beaver 
River  Power  Co.'s  plant  in  Beaver  Canyon  and  13  miles  east  of 
Beaver,  was  at  first  thought  by  its  discoverer  to  be  the  dense  white 
form  of  alunite  but  proved  on  examination  to  be  kaolin,  formed 
through  the  superficial  decomposition  of  rhyolitic  volcanic  rocks. 
A  chemical  analysis  of  the  material  showed  only  0.13  per  cent  of 
potash  (K2O).  One  or  two  other  deposits  have  been  reported,  but 
nothing  definite  has  been  learned  of  them. 

The  Sheep  Rock  deposit  is  a  quartz-alunite  rock  of  too  low  grade  to 
be  of  immediate  commercial  importance  as  a  source  of  alunite  but  of 
sufficient  scientific  interest  to  merit  a  rather  detailed  description. 

SHEEP  BOCK  DEPOSIT. 
LOCATION  AND  EXTENT. 

Sheep  Rock  is  situated  in  the  Newton  mining  district,  at  the  west 
base  of  the  Tushar  Mountains,  about  10  miles  northeast  of  Beaver. 
(See  figs.  13  and  15.)  It  is  a  bare-topped  ledge  of  nearly  circular 
form,  about  900  feet  in  diameter,  and  has  a  gently  rounded  summit 
composed  of  nearly  white  quartz-alunite  rock,  which  in  part  has 
weathered  into  clusters  of  rounded  residual  bowlders.  These  when 
seen  from  a  distance  bear  a  striking  resemblance  to  a  flock  of  sheep 
and  have  given  rise  to  the  name  Sheep  Rock.  The  first  knowledge 
of  alunite  here  was  obtained  early  in  1914,  when  a  specimen  from 
the  northern  part  of  the  ledge  was  sent  to  the  United  States  Geo- 
logical Survey  by  W.  A.  Wilson,  then  manager  of  the  Sheep  Rock 
mine,  and  was  found  by  B.  S.  Butler  to  be  a  mixture  of  alunite  and 


ALUNITE  DEVELOPMENTS  NEAK    M  A  It  VSVALE  AND  BEAVER,  UTAH.    259 

quartz  containing  30  to  40  per  cent  of  quartz.1  The  writer  visited 
the  deposit  in  September,  1914,  and  the  present  description  is  based 
on  his  observations. 


CIIAKACTKR    OK    DKI'OSlT. 


The  relations  of  the  deposit  to  the  andesitic  country  rock  are 
very  obscure.  Its  west,  south,  and  north  sides  are  covered  with 
talus  and  brush  and  pass  beneath  the  alluvium  of  the  valley.  The 
saddle  connecting  it  with  the  andesite  foothills  is  covered  with  float 
and  affords  no  opportunity  to  study  the  contact  in  place.  Study  of 


FIGURE   15. — Geologic   sketch   map   showing  relation   of   the    Sheep   Rock   quartz-alunite 
deposit  near  Beaver,  Utah,  to  country  rock  and  metalliferous  veins. 

the  float,  however,  shows  that  the  two  rocks  merge  within  a  short 
space,  and  that  the  Sheep  Rock  deposit  was  formed  by  the  replace- 
ment of  andesite.  No  definite  connection  writh  neighboring  metal- 
liferous quartz  veins  is  apparent  on  the  surface,  and  none  has  been 
made  in  the  underground  workings  of  the  mine. 

The  material  of  the  deposit  as  a  whole  is  of  uniform  character, 
light-gray  to  pinkish  color,  and  very  fine  grained,  banded  texture. 
A  few  textural  variations,  however,  are  present,  including  brecciated 
and  concretionary  phases  and  rock  in  which  the  porphyritic  texture 
of  the  andesite  is  preserved.  The  alunite  content  also  shows  varia- 

1  Phalen,  W.  C.,  Summary  of  potash  salts  for  1912  :  U.  S.  Geol.  Survey  Mineral  Re- 
sources, 1913.  pt.  2,  p.  91,  1914. 


260         CONTRIBUTIONS   TO  ECONOMIC   GEOLOGY,  1915,  PART  I. 

tions  ranging  from  10  per  cent  or  less  up  to  60  per  cent,  but  as  a 
whole  appears  to  be  rather  uniform  and  to  average  about  30  per  cent, 
equivalent  to  3.5  per  cent  of  potash  (K2O). 

DETAILED  DESCRIPTION. 

The  typical  material  of  the  deposit,  as  viewed  from  a  short  distance,  appears 
grayish  white,  but  most  unweathered  specimens  when  closely  examined  are 
found  to  have  a  faint  to  decided  pinkish  tinge,  a  dense  to  very  fine  grained 
texture,  and  a  distinct  though  rather  fine  banding.  The  banding  strikes  and 
dips  in  various  directions  over  different  parts  of  the  ledge  and  in  many  places 
is  highly  contorted,  the  contortions  showing  no  apparent  order  of  arrangement 
or  relation  to  other  structures,  except  where  they  grade  into  brecciated  rock. 
As  a  rule,  no  mineral  grains  are  recognizable  megascopically,  but  the  alternat- 
ing bands  are  made  up  of  relatively  translucent  and  opaque  material  as  much 
as  a  quarter  of  an  inch  thick.  The  translucent  material  has  all  the  properties  of 
microcrystalline  quartz.  The  opaque  material  is  of  pale  to  moderate  pink  color 
and  in  many,  if  not  most,  places  can  be  distinctly  scratched  by  a  knife  blade. 
Short  veinlets  of  smoky  quartz,  mostly  an  inch  or  less  in  length,  are  common 
between  bands. 

In  thin  section  the  banding  proves  to  be  due  to  alternating  layers  of  rela- 
tively coarse  clouded  quartz  grains  and  a  very  fine  grained  mixture  of  quartz  and 
alunite.  The  coarser  quartz  grains  are  about  0.25  millimeter  in  diameter  and  are 
full  of  minute  bubbles  and  specks.  The  alunite  in  the  fine  grained  mixture  forms 
minute  but  distinct  laths  evenly  scattered  among  fine  interlocking  quartz 
granules.  The  fine  and  coarse  quartz  grains  of  adjacent  bands  have  interlock- 
ing boundaries,  but  the  alunite  grains  end  abruptly  against  the  coarse  quartz 
grains.  There  are,  however,  a  few  relatively  large  alunite  laths,  as  much  as 
0.5  millimeter  in  length,  scattered  among  the  coarse  quartz  grains.  Minute 
grains  of  limonite,  some  distinctly  oxidation  products  after  pyrite  cubes,  are 
thinly  scattered  throughout  the  rock. 

The  brecciated  variety  consists  of  fragments  of  the  typical  finely  banded 
rock  cemented  by  a  siliceous  matrix.  In  thin  section  the  fragments  have  the 
typical  character  and  composition  already  described.  A  few  veinlets  of  alunite 
jire  present  in  them  but  do  not  extend  into  the  matrix,  which  contains  no 
alunite.  The  relations  suggest  that  the  alunite  belonging  to  the  fragments  re- 
crystallized  locally  in  fractures,  but  that  no  second  supply  of  it  was  introduced 
after  the  shattering. 

Close  by  stake  No.  2  the  rock  contains  numerous  white  translucent  patches 
and  streaks  of  chalcedonic  quartz  ranging  from  minute  spots  to  linear  streaks 
a  foot  in  length.  In  thin  section  the  quartz  is  in  part  very  fine  and  even 
grained  and  in  part  composed  of  radiating  crystals,  which  have  evidently 
grown  by  replacement  of  the  quartz-alunite  rock. 

At  a  few  places,  especially  in  the  bowldery  ground  about  100  feet  west  of 
stake  No.  2  (see  fig.  15),  the  rock  lias  a  marked  concretionary  structure,  and 
banding  is  inconspicuous  or  absent.  The  concretions  arc  as  much  as  an  inch 
in  diameter  and  present  a  variety  of  shapes  but  are  not  conspicuously  different 
in  megascopic  character  from  the  matrix.  As  seen  in  thin  section,  they  con- 
sist as  a  rule  of  rudely  fan-shaped  alnnite  crystals  as  much  as  0.5  millimeter 
long,  inclosing  minute  grains  of  quartz  ami  separated  by  minute  linear  siggiv- 
-ates  of  quartz.  The  matrix  consists  mostly  of  the  very  fine  grained  quartz 
sprinkled  with  minute  alunite  laths  in  roughly  concentric  arrangement, 
suggestive  of  crowding  by  the  growth  of  the  concretions. 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    261 

The  highest-grade  material,  which  has  a  moiv  distinctly  pink  color  than 
the  rest  of  the  deposit,  was  found  in  the  tains  on  the  north  slope  of  the  area. 
It  has  in  part  the  typical  banded  structure  and  in  part  a  blotchy  appearance, 
the  predominating  bands  or  blotches  of  pink  alternating  with  others  of  gray 
color.  Some  of  the  gray  blotches  contain  small  cavities  representing  a  dis- 
solved mineral,  probably  feldspar.  In  thin  section  the  pink  part  is  seen  to 
consist  mostly  of  a  mass  of  alimite  inclosing  minute  grains  of  quartz.  The 
alunite  occurs  mainly  as  a  1'elty  mass  of  minute  laths,  in  which  are  scaticred 
larger  crystals,  single  or  in  feathery  aggregates  as  much  as  a  millimeter  long. 
The  relation  of  the  larger  to  the  smaller  crystals  suggests  that  the  former  have 
grown  at  the  expense  of  the  latter.  Alunite  makes  up  about:  (50  per  cent:  of  1 1n- 
whole.  The  gray  areas  consist  of  very  fine  quartz  aggregates,  the  borders  of 
which  appear  to  have  been  partly  replaced  by  alunite.  The  quartz  areas  con- 
tain a  few  grains  ()..">  millimeter  or  less  in  diameter,  which  are  evidently 
quart/  phenocrysts  practically  unaffected  during  the  replacement  of  porphyry 
by  the  quartz-alunite  mixture;  they  also  include  a  few  minute  grains  and 
streaks  of  limonite,  the  grains  preserving  the  cubic  outline  of  original  pyrite 
crystals. 

Gradation  into  the  country  rock  is  marked  by  a  pale-pink  dense  rock  in 
which  a  few  megascopic  quartz  grains  and  the  outlines  of  original  feldspar 
crystals  are  preserved.  In  thin  section  the  feldspar  phenocrysts  prove  to  be 
largely  replaced  by  fine  aggregates  of  alunite,  and  faint  outlines  of  original 
black  silicates  are  suggested  by  fine  quartz  areas  dusted  with  black  specks  and 
grains,  the  largest  of  which  suggest  pyrite.  Quartz  phenocrysts  are  very  scarce. 
The  groundmass  is  extremely  fine  grained  and  consists  almost  wholly  of 
quartz  with  a  little  alunite  and  pyrite.  This  variety  is  similar  to  the  altered 
wall  rock  of  the  Marysvale  alunite  veins. 

RELATION   TO   METALLIFEROUS  DEPOSITS. 

The  rock  last  described  is  very  different  from  the  altered  wall 
rock  of  the  main  vein  in  the  Sheep  Eock  mine,  which  is  a  typical 
sericitized  andesite.  The  original  minerals  of  this  rock,  both  pheno- 
crysts and  groundmass,  have  been  replaced  by  very  fine  grained 
mixtures  of  quartz  and  sericite,  with  about  3  per  cent  of  pyrite  in 
small  grains.  This  rock  contains  gold  to  the  extent  of  a  few  dollars 
to  the  ton  and  is  classed  as  milling  ore. 

No  microscopic  alunite  was  found  in  the  sericitized  rock,  and  there 
was  no  opportunity  to  study  the  relations  between  sericitization 
und  alunitization  or  between  the  metalliferous  quartz  vein  and  the 
quartz-alunite  body.  The  vein  is  of  the  same  type  as  the  metallifer- 
ous veins  in  the  Marysvale  district,  and  it  therefore  seems  probable 
that  the  quartz-alunite  body  bears  the  same  general  relation  to  it  as 
the  alunite  veins  in  the  Marysvale  region  are  thought  to  bear  to  the 
neighboring  metalliferous  veins,  but  here,  as  in  the  Marysvale  region, 
no  direct  connection  between  the  two  types  of  deposits  has  been 
proved.  It  is  hoped  that  future  development  along  the  Sheep  Rock 
vein  will  disclose  the  relation. 


262          CONTRIBUTIONS  TO   ECONOMIC   GEOLOGY,  1915,   PART  I. 

ORIGIN. 

In  view  of  this  deficiency  of  critical  evidence,  any  statement  con- 
cerning the  origin  of  the  Sheep  Rock  quartz-alunite  deposit  must  be 
regarded  merely  as  a  working  hypothesis.  The  shape  of  the  deposit 
and  its  position  with  respect  to  the  neighboring  metalliferous  veins, 
especially  the  worked  vein  of  the  Sheep  Rock  mine,  suggest  that  the 
rising  vein-forming  solutions  were  locally  impounded  and  deflected 
along  a  permeable  bed  beneath  some  impervious  layer  of  porphyry 
which  is  now  removed  by  erosion.  Physical  conditions  at  this  place 
were  such  that  well-crystallized  quartz  and  sericite,  which  charac- 
terize the  metalliferous  veins,  were  no  longer  formed.  Instead  the 
porphyry  was  permeated  by  silica,  accompanied  by  the  sulphate  and 
sulphide  radicles.  These  radicles  converted  the  potassium  and 
aluminum  largely  into  alunite  and  a  small  amount  of  the  iron  into 
pyrite.  It  is  possible  that,  as  in  the  Marysvale  veins,  some  potas- 
sium and  aluminum  were  introduced  by  the  solutions,  but  the  aver- 
age percentages  of  these  elements  in  the  Sheep  Rock  deposit,  as 
shown  by  analyses  1  and  2,  on  page  263,  is  little,  if  any,  more  than 
those  in  the  original  porphyry. 

The  banded  structure  of  the  deposit  bears  a  strong  resemblance  to 
that  of  the  siliceous  ores  seen  by  the  writer  in  the  Tintic  mining  dis- 
trict and  recently  described  by  Lindgren,1  who  attributes  the  band- 
ing to  diffusion  in  the  replacement  body  of  colloidal  silica  while  the 
mass  was  still  in  a  soft  state.  If  this  mode  of  replacement  is  accepted 
for  the  Sheep  Rock  deposit,  the  numerous  contortions  in  the  banding 
may  be  attributed  to  deformation  before  the  mass  became  rigid,  and 
the  brecciated  parts  to  deformation  after  the  mass  as  a  whole  had 
become  rigid  but  while  there  was  still  sufficient  fluid  or  gelatinous 
silica  to  enter  the  interstices  and  cement  the  fragments. 

Along  the  original  margins  of  the  deposit,  where  the  replacing 
solution  was  weak  or  was  more  rapidly  consolidated,  there  was  evi- 
dently insufficient  opportunity  for  complete  replacement  and  de- 
velopment of  banding,  and  the  porphyritic  texture  of  the  replaced 
rock  was  preserved.  The  local  concretionary  structure  evidently 
marks  a  tendency  of  the  alunite  to  concentrate,  possibly  while  the 
mass  was  still  gelatinous.  The  presence  of  alunite  in  cracks  later  than 
the  banding  and  the  presence  of  large  alunite  crystals  growing  at 
the  expense  of  small  ones  indicate  a  tendency  of  the  mineral  to  con- 
centrate even  after  the  rock  had  hardened. 

As  contrasted  with  the  Marysvale  deposits,  the  Sheep  Rock  deposit 
was  formed  almost  wholly  by  the  replacement  of  porphyry,  and  the 
two  minerals,  alunite  and  quartz,  were  intimately  mixed,  whereas 

1  Lindgren,  Waldcmar,  Processes  of  mineralization  and  enrichment  in  the  Tintic  mining 
district :  Econ.  Geology,  vol.  10,  No.  3,  pp.  233-235,  1915. 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    263 

those  near  Marysvale  were  formed  for  the  most  part  in  open  fis- 
sures, with  ample  opportunity  for  the  segregation  of  pure  alunite, 
and  only  to  a  minor  extent  by  replacement.  This  comparison  does 
not  imply  that  the  available  alunite  was  the  same  in  each  locality. 
The  solutions  in  the  Marysvale  area  may  have  contained  a  larger 
amount  of  the  constituents  of  alunite,  in  addition  to  being  favored 
with  a  better  opportunity  to  deposit  the  mineral  in  segregated 
masses. 

CHEMICAL  COMPOSITION. 

The  three  following  partial  analyses  of  the  quartz-alunite  rock, 
two  of  average  samples  and  one  the  hi'gh-grade  variety,  were  made  by 
R.  K.  Bailey,  of  the  United  States  Geological  Survey : 

Analyses  of  quartz-alunite  rock  from  Sheep  Rock  deposit. 


1 

2 

3 

Silica  (SiO2) 

60.83 

70.78 

30.12 

Sulphate  radicle  (SO3)  

13.83 

10.56 

26.53 

Potash  (K2O).  . 

3.89 

2.90 

6.87 

1.  Average  sample  at  summit  of  Sheep  Rock. 

2.  Average  sample  around  stake  No.  2  (fig.  15). 

3.  High-grade  sample,  north  slope  of  Sheep  Rock. 

In  analysis  1  the  ratio  of  the  sulphate  radicle  to  potash  is  almost 
exactly  that  of  pure  potash  alunite.  Calculation  from  these  data 
gives  over  13  per  cent  of  alumina  and  35.6  per  cent  of  alunite.  In 
analysis  2  there  is  an  excess  of  0.6  per  cent  of  the  sulphate  radicle 
over  the  ratio  between  the  sulphate  radicle  and  potash  for  alunite. 
This  small  excess  may  have  been  present  in  the  soda  alunite  mole- 
cule. The  calculated  percentage  of  alumina  is  only  9.5  per  cent  and 
of  alunite  25.7  per  cent.  In  analysis  3  the  excess  of  the  sulphate  radi- 
cle is  3.2  per  cent.  This  also  may  have  been  present  in  soda  alunite. 
The  calculated  percentage  of  alumina  in  No.  3  is  22.3  per  cent  and 
that  of  alunite  60.3  per  cent. 

COMMERCIAL  VALUE. 

The  percentage  of  alunite,  and  therefore  of  potash,  is  much  too 
low  throughout  most  of  the  Sheep  Rock  deposit  to  be  of  any  com- 
mercial value.  Only  in  the  talus  at  the  north  end  of  the  deposit 
has  material  of  promising  grade  been  found,  and  only  a  little  of 
this  is  in  sight.  Even  the  high-grade  material,  however,  contains 
so  much  silica  that,  when  compared  with  the  practically  pure  alunite 
in  the  veins  near  Marysvale,  the  cost  of  crushing  and  calcining  it, 
to  say  nothing  of  the  cost  of  transportation,  will  probably  be  prohibi- 
tive for  any  but  local  use.  The  presence  of  alunite  in  the  Sheep 


264         CONTRIBUTIONS  TO  ECONOMIC   GEOLOGY,  1915,  PART  I. 

Rock  deposit,  however,  indicates  that  the  solutions  which  deposited 
alunite  were  active  in  the  extreme  western  as  well  as  the  eastern  part 
of  the  Tushar  Mountains  and  that  the  hills  around  Sheep  Rock  will 
be  promising  ground  for  alunite  prospecting. 

UTILIZATION   OF  ALUNITE. 

PRODUCTS. 

Although  alunite  has  been  mined  for  many  years  in  foreign  coun- 
tries as  a  source  of  potash  alum,  the  principal  attention  has  been 
given  to  it  in  this  country  as  a  possible  domestic  source  of  potash. 
The  extraction  of  potassium  sulphate  from  it  on  a  commercial  scale 
appears  now  to  have  been  accomplished.  Possible  by-products  in 
the  extraction  of  potassium  sulphate  are  alumina  and  sulphuric  acid. 
The  successful  production  of  the  alumina  or  its  derived  products 
on  a  commercial  scale  appears  to  be  a  possibility,  but  there  is  no 
prospect  of  the  production  of  sulphuric  acid  at  present. 

POTASSIUM  •••••••i  SULPHATE 

As  already  stated,  a  demonstration  by  W.  T.  Schaller  that  the 
simple  potassium  sulphate  instead  of  potash  alum  could  be  easily 
extracted  from  alunite  simply  by  leaching  the  calcined  mineral  with 
water  was  published  by  the  United  Statej  Geological  Survey  on 
January  9,  1912.1  Schaller's  observations  are  as  follows : 

Laboratory  experiments  showed  that  on  igniting  the  powdered  alunite  all  of 
the  water  and  three-fourths  of  the  sulphuric  acid  are  volatized.  On  leaching 
the  residue  with  water  the  potassium  sulphate  is  dissolved,  leaving  the  insoluble 
aluminum  oxide  behind. 

The  average  amount  of  potassium  sulphate  leached  from  the  ignited  mineral 
powder  is  17.9  per  cent  of  the  original  material  used.  As  the  coarsely  crystal- 
lized alunite  was  found  to  contain  19.4  per  cent  of  potassium  sulphate,  92 
per  cent  of  the  total  potash  present  was  obtained  by  simple  ignition  and  subse- 
quent leaching. 

It  is  worth  noting  that,  according  to  the  laboratory  experiments,  32.7  per 
cent  of  the  ignited  alunite  consists  of  available  potassium  sulphate,  which 
can  be  extracted  by  simple  water  lowhing  nnd  evaporation.  The  remaining 
67.3  per  cent  consists  of  nearly  pure  aluminum  oxide. 

TTaggaman2  found  that  a  large  quantity  of  water  was  required 
to  free  the  ignited  residue  of  alunite  from  soluble  salts  and  that  the 
subsequent  evaporation  was  tedious  and  expensive,  but  the  process 
has  finally  been  worked  out  on  a  commercial  scale  by  the  Mineral 
Products  Corporation.  The  following  description  of  the  process 

1  T".  B.  Oool.  Survey  P.ull.  .",11,  pp.  ns.  01,  1912;  also  announced  in  a  notice  given  to  the 
press  for  publication  on  Dec.  18,  1911   <r.  S.  c;.-ol.  Surv.-y  I'rcss  Hull.  30). 
*Waggaman,  W.  II.,  U.  S.  Dept.  Agr.  Bur.  Soils  Circ.  70,  4  pp.,  July  31,  1912. 


ALUNITE  DEVELOPMENTS  NEAR  MARVSVALE  AND  BEAVER,  UTAH.    265 

is  based  on  'information  furnished  by  V.  C.  Heikes,  of  the  United 
States  Geological  Survey,  who  saw  the  plant  in  operation. 

From  the  ore  bins  at  the  mill  the  alunite  passes  through  a  gyratory 
crusher,  then  through  a  set  of  rolls,  and  thence  is  delivered  to  a 
storage  bin.  This  material  is  mixed  with  powdered  slack  coal  and 
is  fed  into  a  rotary  kiln  in  which  it  is  roasted.  The  roasted  material 
is  elevated  to  a  storage  bin  from  which  it  is  drawn  off  into  a  digester. 
In  the  digester  it  is  mixed  with  water  and  the  sulphate  of  potassium 
dissolved  out.  The  charges  from  the  digester  are  stored  in  wooden 
tanks.  From  these  tanks  the  mixture  is  pumped  into  a  filter  press 
where  the  insoluble  alumina  and  the  water-soluble  potash  are  sepa- 
rated. 

The  solution  is  then  evaporated  in  triple-effect  vacuum  pans.  The 
sulphate  of  potassium  crystals  are  separated  out,  drained,  and  dried. 
The  dried  powder  is  pulverized,  screened,  and  sacked  for  shipment. 

The  boiler  plant  uses  slack  coal  for  fuel.  Boilers  having  a  rating 
of  600  horsepower  produce  steam  for  driving  three  engines,  running 
the  machinery  of  the  plant.  The  exhaust  steam  is  used  for  evaporat- 
ing the  solutions  and  drying  the  product. 

The  capacity  of  the  first  unit  of  the  plant  is  estimated  to  be  from 
25  to  35  tons  of  sulphate  of  potassium  a  day.  In  addition  to  the 
valuable  sulphate  of  potassium,  the  operators  expect  to  gain  some 
return  from  the  filter  cake  left  after  the  potash  solution  has  been 
removed  from  the  calcined  material.  This  cake  consists  of  nearly 
pure  alumina  and  may  be  used  for  making  refractory  brick,  for  it 
is  reported  to  withstand  temperatures  as  high  as  2,020°  C.  It  may 
also  prove  to  be  available  for  making  aluminum. 

The  mill  is  reported  to  be  the  first  of  its  kind  built  in  the  United 
States  to  treat  alunite,  and  operation  of  the  first  unit  was  begun  on 
September  15,  1915,  when  some  alunite  was  put  through  the  crusher. 
Thereafter  each  part  of  the  machinery  was  gradually  tested  until, 
by  October  6,  fully  200  tons  of  alunite  had  been  distributed  through 
the  plant.  On  October  5  about  20  tons  of  filter  cake  reported  to 
contain  about  65  per  cent  of  alumina  (A12O3)  was  discharged,  and 
the  saturated  solution  of  potassium  sulphate,  about  85,000  gallons, 
had  accumulated  in  the  evaporators,  which  were  placed  in  commis- 
sion on  October  6.  On  October  7  the  first  potassium  sulphate  was 
produced  and  was  said  to  be  about  99  per  cent  pure  and  2  tons  in 
quantity.  On  October  20  the  first  carload,  aggregating  28  tons  of 
potassium  sulphate  that  analyzed  more  than  93  per  cent  pure,  is 
reported  to  have  been  shipped  in  cotton  bags  to  the  Armour  Ferti- 
lizer Works  at  Jacksonville,  Fla.1  Three  cars  are  reported  to  have 
been  shipped  within  the  first  month. 

1  Manufacturers'  Record,  Oct.  21,  1915,  p.  r,i'. 


266         CONTRIBUTIONS  TO  ECONOMIC   GEOLOGY,  1915,  PART  I. 

The  mill  is  situated  about  5  miles  southwest  of  Marysvale  and  2 
miles  west  of  Sevier  River,  near  the  mouth  of  Little  Cottonwood 
Canyon.  The  alunite  vein,  on  the  Gillan-Custer  claims,  is  4  miles 
farther  west  by  wagon  road.  The  mined  alunite  is  conveyed  by  an 
aerial  tramway  6,200  feet  long,  with  a  fall  of  1,900  feet,  to  a  bin  at 
the  creek  level,  from  which  it  is  carried  by  wagons  over  a  down- 
grade road  of  3J  miles  to  the  mill.  The  tramway,  under  present 
conditions,  has  a  rated  capacity  of  12J  tons  of  alunite  an  hour. 

Plans  are  reported  for  the  erection  of  a  plant  by  the  Utah  Potash 
Co.  for  extracting  potassium  sulphate  and  alumina  from  the  alunite 
in  the  deposits  of  the  Florence  Mining  &  Milling  Co. 

POTASH  ALUM. 

Potash  alum  is  a  hydrous  sulphate  of  aluminum  and  potassium 
(K2O.A12O3.4SO3.24H2O)  containing  11  per  cent  alumina,  10  per 
cent  of  potash,  34  per  cent  of  sulphur  trioxide,  and  45  per  cent 
of  water.  The  quantities  and  values  of  alum  (principally  potash 
alum)  and  aluminum  sulphate  produced  in  the  United  States  from 
1910  to  1914,  inclusive,  and  the  total  imports  of  aluminum  salts  are 
shown  in  the  following  table : x 

Production  and  imports  of  aluminum  salts  into  the  United  States,  1910-1914,  in 

short  tons. 


Year. 

Production. 

Imports.o 

Alum. 

Aluminum  sulphate. 

Quantity. 

Value. 

Quantity. 

Total 
value. 

Value 
per  ton. 

Quantity. 

Total  value. 

Value 
per  ton. 

1910 

9,090 
10,468 
9,246 
9,605 
18,238 

$300,  763 
329,686 
293,  995 
312,822 
565,  989 

$33.09 
31.49 
31.80 
32.57 
31.03 

126,792 
134,077 
150,427 
157,  749 
164,954 

$2,  447,  652 
2,  743,  336 
2,  909,  495 
2,  977,  708 
2,942,572 

$19.30 
20.46 
19.34 
18.88 
17.84 

2,127 
2,283 
3,342 
2,702 
2,891 

$53,  671 
56,833 
84,606 
66,549 
73,028 

1911 

1912  

1913 

1914  

a  Includes  alumina,  aluminum  hydrate,  or  refined  bauxite,  alum,  alum  cake,  aluminum  sulphate, 
aluminous  cake,  and  alum  in  crystals  or  ground. 

The  potash  in  the  domestic  alum  is  imported,  and  the  alumina  is 
derived  from  bauxite  mined  chiefly  in  Alabama,  Georgia,  and 
Tennessee,  with  small  quantities  from  Arkansas.  Only  bauxite  con- 
taining less  than  2  per  cent  of  iron  oxide  is  used  in  the  manufacture 
of  alum,  aluminum  sulphate,  and  other  aluminum  salts.  The  plants 
manufacturing  potash  alum  and  other  aluminum  salts  are  all  east  of 
Mississippi  Kiver,  but  the  practicability  of  establishing  a  plant  in 
Utah  is  worthy  of  careful  consideration. 


1  Phalen,  W.  C.,  The  production  of  bauxite  and  aluminum  In  1914 :  U.  S.  Geol.  Survey 
Mineral  Resources,  1914,  pt.  1,  p.  208,  1915. 


ALUNITE  DEVELOPMENTS  KEAR  MARYSVALE  AND  BEAVER,  UTAH.    267 

The  description  of  the  process  of  manufacturing  potash  alum  from 
alunite  in  foreign  countries,  which  was  reviewed  by  Butler  and  Gale,1 
is  here  repeated  for  the  reader's  convenience. 

A  considerable  amount  of  alum  is  prepared  from  alunite.  Alunite  contains 
the  elements  of  potassium  alum,  basic  aluminum  sulphate,  and  free  alumina. 
In  Sicily  it  is  made  into  heaps  and  calcined  in  the  open  air.  At  Tolfa,  where 
the  manufacture  is  carried  out  on  a  larger  scale,  the  roasting  is  conducted  in 
furnaces  like  limekilns,  lined  with  refractory  materials.  The  mineral  is  heated 
in  large  pieces  by  the  flame  without  direct  contact  with  the  fuel  until  sulphur 
dioxide  begins  to  escape.  The  calcination  requires  about  six  hours,  the  mass 
losing  about  35  per  cent  of  water.  During  the  ignition  the  excess  of  alumina 
beyond  that  necessary  to  produce  alum  is  rendered  insoluble  and  no  longer  has 
the  property  of  precipitating  basic  sulphates  from  the  solution.  The  calcined 
mass  is  exposed  to  the  air  upon  a  clay  floor  for  some  weeks,  during  which  time 
it  is  occasionally  moistened.  The  mudlike  product  is  agitated  in  boilers  with 
water  at  70°  C.,  and  the  clear  decanted  liquid,  of  density  10°-12°  B.,  is  evap- 
orated to  32°  B.  and  crystallized  in  small  wooden  tubs.  The  crystals  are 
cubic,  opaque,  and  reddish  from  the  presence  of  ferric  oxide.  This  iron  is,  how- 
ever, quite  insoluble  and  may  be  separated  by  recrystallization ;  the  soluble 
iron  is  said  to  be  less  than  0.005  per  cent.  In  this  way  "  Roman  alum  "  was 
formerly  largely  produced.  On  account  of  their  great  purity  the  red  crystals 
were  much  sought  after. 

Alunite  is  now  largely  converted  into  alum  by  treatment  with  sulphuric  acid 
and  addition  of  potassium  sulphate.  Guyot2  has  examined  this  process  and 
recommends  the  following  method: 

On  ignition  of  alunite  the  free  alumina  is  first  rendered  anhydrous  and  soluble 
in  sulphuric  acid  ;  at  a  higher  temperature  the  basic  sulphates  become  soluble,  but 
if  the  temperature  be  allowed  to  rise  too  high  the  alumina  becomes  vitrified 
and  is  insoluble.  Guyot  recommends  ignition  at  800°  C.  for  three  hours  as 
the  best  means  of  rendering  the  maximum  of  both  these  substances  soluble. 
The  composition  of  the  calcined  mass  is  determined,  and  acid  is  used  in  pro- 
portion to  the  amount  of  soluble  sulphate  contained.  For  a  product  of  the 
following  composition,  K2SO4,  14  per  cent;  A12O3.3SO3  (present  as  alum),  26.55; 
A12O3.3SO3  (free),  6.56;  A12O3  (free),  18.58;  OH2,  11.90;  Fe2O3,  0.80;  siliceous 
residue,  21.61  per  cent,  the  proportions  given  below  would  be  most  satisfactory. 
Into  a  clay  oven  is  poured  12.5  tons  of  sulphuric  acid  of  52°  B.  diluted  to  30° 
B.  and  heated  to  80°  or  90°  C.  Eight  tons  of  the  calcined  mineral  is  then  added 
in  portions  and  well  stirred.  After  the  whole  has  been  added  the  liquid  is  left 
for  two  hours  then  evaporated  to  38°  B.  and  treated  with  2.7  tons  potassium 
sulphate.  The  process  up  to  this  point  occupies  10  hours ;  after  a  further  period 
of  13  hours  the  clear  liquid  is  decanted  off;  its  density  should  not  exceed  42° 
B.  The  muddy  liquid  remaining  is  reduced  to  24°  B.  by  the  addition  of  mother 
liquor  from  a  previous  crystallization,  stirred,  allowed  to  settle,  drawn  off 
clear,  mixed  with  the  first  decantate,  and  crystallized  in  a  vat.  After  one  day 
the  crystals  are  removed,  redissolved,  and  recrystallized.  The  muddy  residue 
is  crystallized  out  for  a  further  crop  of  alum.  The  total  yield  of  alum  is  about 

ill.  S.  Geol.  Survey  .Bull.  511,  pp.  59-60,  1912;  quoted  from  Thorpe,  T.  E.,  Dictionary 
of  applied  chemistry,  London,  1890,  p.  78. 

2  Guyot,  M.  P.,  Sur  la  richesse  industrielle  de  1'alunite  crue,  en  poudro  :  Paris  Acad. 
Sci.  Compt.  Rend.,  vol.  95,  pp.  G93,  694  ;  Experiences  sur  la  calcination  de  1'alunite  en 
poudre,  destinee  a  la  fabrication  de  1'alum  et  du  sulfate  1'alumino  :  Idem,  pp.  1001-1003. 


268         CONTRIBUTIONS  TO  ECONOMIC   GEOLOGY,  1915,  PART  I. 

2.3  times  the  original  weight  of  ore.    The  insoluble  matter  contains  3  per  cent 
alumina  and  2.01  per  cent  potassium  sulphate,  in  addition  to  silica,  etc. 

According  to  C.  Schwartz,1  the  best  temperature  for  the  roasting  is  500°  C., 
and  the  acid  used  should  have  a  density  between  1.297  and  1.530. 

The  summary  concerning  the  utilization  of  the  Australian  deposit 
at  Bullahdelah  is  contained  in  the  following  paragraphs : 2 

The  following  is  a  process  by  which  alum  is  manufactured  from  alunite: 
The  mineral  is  ground  and  then  calcined  in  reverberatory  furnaces,  to  dehy- 
drate it  and  drive  off  part  of  the  SO3.  It  is  next  treated  with  a  weak  solution 
of  sulphuric  acid  in  lead-lined  tanks,  heated  to  boiling  point  by  steam  jets.  The 
liquor  is  allowed  to  settle  in  the  same  vats,  and  the  clear  solution  is  run  off 
into  crystallizing  tanks,  which  are  kept  in  constant  agitation  while  cooling,  the 
alum  crystallizing  out  and  sulphate  of  alumina  remaining  in  solution.  The 
residue  in  the  vat  is  boiled  again  with  water,  and  the  solution  run  off  again  in 
the  same  way.  The  liquor  containing  sulphate  of  alumina  is  then  returned  to 
the  vats  and  sufficient  of  the  calcined  mineral  added  to  completely  neutralize 
any  free  acid.  It  is  then  heated  to  boiling  point  and  ebullition  continued  until 
partial  reversion  takes  place,  the  reversion  being  accompanied  by  a  precipitation 
of  the  hydrated  ferric  oxide. 

The  alum,  after  collection,  is  washed  and  then  refined  in  vats,  similar  to  but 
deeper  than  those  originally  employed,  and  the  concentrated  solution  is  run  into 
reaching  tuns  in  which  it  is  crystallized ;  it  is  then  broken  up  and  packed  ready 
for  the  market. 

The  sulphate  of  alumina  solution,  after  all  the  alum  has  been  crystallized 
from  it,  is  concentrated  in  small  vats  heated  with  steam  coils,  and  the  lower 
qualities  of  sulphate  of  alumina  are  formed  by  running  the  liquor  onto  lead 
tables  and  breaking  the  solidified  material  into  blocks,  the  higher  qualities 
(containing  over  17  per  cent  of  soluble  alumina)  being  cast  on  copper  trays. 
These  higher  qualities,  which  vary  in  color  from  yellow  to  green  in  the  slabs, 
are  then  ground  in  a  disintegrator,  and  the  material  assumes  a  snow-white 
appearance. 

It  is  of  course  feasible,  by  the  addition  of  K2S(>4,  to  convert  the  whole  of  the 
alumina  contained  in  the  stone  into  alum  if  desired,  but  the  more  profitable 
method  of  treatment,  when  the  better  classes  of  sulphate  of  alumina  can  be  sold 
at  standard  prices,  is  to  make  only  so  much  alum  as  there  is  sulphate  of  potash 
present  in  the  stone  to  produce,  and  convert  the  rest  of  the  alumina  into  soluble 
sulphate  of  alumina  (of  commerce). 

Sulphur  may  be  obtained  by  distilling  the  mineral  in  the  presence  of  any  re- 
ducing gas  like  coal  gas.  Sulphuric  acid  may  also  be  distilled  from  the  mineral. 
Heating  with  carbonate  of  baryta  produces  aluminate  of  potash. 

The  following  extract  from  a  recent  consular  report 3  gives  a  little 
additional  information  on  the  industry  at  Bullahdelah: 

The  stone  yields  on  an  average  80  per  cent  of  alum.  According  to  the  statis- 
tics for  the  mining  industry  of  New  South  Wales,  the  output  of  alum  for  the 
years  1856  to  1908  was  valued  at  $450,000  and  for  1908  to  the  end  of  1913 
$190,000.  Since  the  year  1908  about  1,200  tons  of  the  rock  have  been  taken  out 

1  Ueber  die  Aufschliessung  des  romischen  Alunits :  Deutsch.  chem.  Gesell.  Ber.,  vol.  17, 
p.  2887. 

2Pittman,  E.  P.,  Alunite  or  alumstone  in  Now  South  W:il«'s  :  New  South  Wales  Geol. 
Survey  Kept.,  1901,  pp.  419-41M). 

'Sullivan,  L.  N.  (consul  at  Newcastle,  N.  S.  W.),  Dally  Cons,  and  Trade  Repts.  No.  199, 
p.  991,  Bur.  Foreign  and  Domestic  Commerce,  Aug.  25,  1915. 


ALUNITE  DEVELOPMENTS  NEAR  MARYSVALE  AND  BEAVER,  UTAH.    269 

annually  and  shipped  to  England  for  treatment,  where  the  alum  could  be  ex- 
tracted much  more  cheaply  than  was  possible  here.  The  Australian  Alum  Co. 
(Ltd.)  is  the  operating  company,  with  head  offices  at  109  Pitt  Street,  Sydney. 

ALUMINA  AND  ALUMINUM  PRODUCTS. 

The  possible  derivation  of  alumina  as  a  by-product  in  the  extrac- 
tion of  potash  from  alunite  has  already  been  mentioned.  Experi- 
ments on  the  direct  extraction  of  alumina  from  high-grade  alunite 
(see  analyses  1,  4,  and  5,  p.  246)  have  shown  that  the  process  works 
well  and  may  be  a  commercial  success  if  freight  rates  from  Utah  to 
eastern  aluminum-manufacturing  plants  are  not  prohibitive.  As 
an  offset  to  the  freight  rates,  however,  is  the  fact  that  the  alumina 
produced  from  high-grade  alunite  is  purer  than  the  bauxite  ores  of 
the  Southern  States.  The  low-grade  mineral,  corresponding  to 
analysis  2  on  page  246,  contains  too  much  silica  to  be  used  as  an  ore 
of  aluminum. 

The  question  of  erecting  a  western  plant  for  extraction  of  alumi- 
num may  be  found  to  deserve  consideration.  In  a  recent  paper 
by  Lyon  and  Keeny,  of  the  United  States  Bureau  of  Mines,1  the  state- 
ment is  made  that  "  all  processes  for  the  extraction  of  aluminum  from 
silicates  are  still  very  much  in  the  experimental  stage."  As  alunite  is 
a  sulphate,  not  a  silicate,  and  can  be  obtained  practically  free  from 
silica,  its  availability  appears  more  promising.  The  extraction  of 
both  potash  and  alumina  from  the  same  lot  of  ore  should  apparently 
go  further  toward  making  a  successful  industry  than  the  extraction 
of  either  product  alone. 

Other  products,  now  obtained  from  the  mineral  bauxite,  a  hydrous 
oxide  of  aluminum,  may  also  be  derived  from  the  residue  left  after 
the  extraction  of  potassium  sulphate  from  alunite.  These  are  the 
different  aluminum  salts,  refractory  bricks,  alundum  (fused  alumina) , 
and  calcium  aluminate.  In  the  manufacture  of  refractory  bricks, 
the  purer  the  alumina  the  more  refractory  the  resulting  product, 
but  it  is  probable  that  the  rather  siliceous  residues  from  the 
less  pure  grades  of  alunite,  such  as  that  represented  by  analysis  2. 
page  246,  will  be  satisfactory  for  this  purpose,  whereas  the  residues 
practically  free  from  silica  are  especially  desirable  for  the  manufac- 
ture of  metallic  aluminum.  Alundum  is  used  as  an  abrasive  and  is 
finding  an  extended  use  in  the  refractory  industries.  Calcium  alumi- 
nate is  used  to  give  a  quick  set  to  plasters.  It  is  possible  that  the 
alumina  residue  at  the  Marysvale  plant  may  find  a  direct  use,  and 
it  is  reported  that  experiments  to  determine  this  point  are  under  way. 
Further  information  on  the  production  and  manufacture  of  alumi- 
num and  its  products  is  given  in  the  annual  reports  on  bauxite  and 

1  Lyon,  D.  A.,  and  Keeny,  R.  M.,  Electro-metallurgy  of  aluminum  in  the  West  (presented 
at  September  meeting  of  American  Institute  of  Mining  Engineers)  :  Abstract  published  in 
Min.  and  Eng.  World  Aug.  7,  1915. 


270          CONTRIBUTIONS   TO   ECONOMIC   GEOLOGY,   1915,   PAET   I. 

aluminum  by  W.  C.  Phalen,  of  the  United  States  Geological  Survey, 
in  Mineral  Resources  for  the  years  1908  to  1914,  inclusive. 

SULPHURIC  ACID  AND  SULPHUR. 

The  manufacture  of  sulphuric  acid  in  connection  with  the  prepa- 
ration of  potassium  sulphate  and  alumina  has  also  been  suggested, 
and  in  certain  patents  issued  for  apparatus  for  treating  alunite 
means  have  been  devised  for  conserving  the  fumes  given  off  in  roast- 
ing. It  is  stated  by  Phalen,1  however,  that  owing  to  the  expense  of 
the  process  and  to  the  small  market  for  sulphuric  acid  in  the  West 
at  the  present  time,  it  is  very  unlikely  that  the  conservation  of  sul- 
phuric acid  from  alunite  will  be  seriously  considered  for  some  years 
at  least. 

It  has  been  suggested  that  sulphur  may  be  obtained  by  distilling 
the  alunite  in  the  presence  of  any  reducing  gas.  The  production  of 
sulphur  by  such  a  method  has  evidently  not  been  considered  by  those 
interested  in  the  Marysvale  deposits,  and  it  is  not  likely  to  prove 
practical  in  view  of  the  large  amount  of  sulphur  produced  so  cheaply 
in  Louisiana  and  Texas,  and  for  the  further  and  important  reason 
that  the  production  of  sulphur  from  its  oxides  (the  "  sulphur  fumes  " 
from  smelters)  has  not  yet  progressed  beyond  the  experimental  stage. 

FERTILIZER. 

Owing  to  the  slowness  and  expense  of  extracting  potassium  sul- 
phate from  alunite  by  leaching  Waggaman2  suggested  that  it 
might  be  more  economical  to  use  ignited  alunite  directly  as  a  fer- 
tilizer. Experiments  by  Skinner  and  Jackson3  afford  some  infor- 
mation on  this  question.  These  experiments  show  that  raw  alunite 
used  in  amounts  equivalent  to  25  to  500  pounds  of  K2O  per  acre 
increased  growth  from  10  to  20  per  cent.  The  growth  when  the 
raw  alunite  was  used  was  not  so  good  as  with  similar  amounts  of 
potassium  sulphate  and  potassium  chloride,  but  the  increase  in 
growth  with  calcined  alunite  ranged  from  35  to  43  per  cent,  the  aver- 
age being  40  per  cent,  which  was  about  the  same  as  that  with  potas- 
sium sulphate  and  greater  than  that  with  potassium  chloride. 

i  Phalen,  W.  C.,  Potash  salts,  1914  :  U.  S.  Geol.  Survey  Mineral  Resources,  1914,  pt.  2, 
p.  21,  1915. 

a  U.  S.  Dept.  Agr.  Bur.  Soils  Circ.  70,  July  31,  1912. 

3  Skinner,  J.  J.,  and  Jackson,  A.  M.,  Alunite  and  kelp  as  potash  fertilizers :  U.  S.  Dept. 
Agr.  Bur.  Soils  Clrc.  76,  5  pp.,  Apr.  10,  1913. 


